Abstract:
Embodiments of the present invention provide devices (tags with sensors), systems, and methods to determine states (such as, but not limited to, complex impedance) of materials-of-interest, such as tissue-of-interest, implants, and construction members, to name a few, in a non-invasive and contactless way; and using comparatively safe and/or low energy electromagnetic radiation, such as radio waves. Negligible-sized wireless-tags with sensors are implanted in such materials-of-interest. Using wireless communication and imaging technology, the states of the materials-of-interest may be monitored; which may allow non-invasive and contactless detection of problems such as cracking, bending, excessive pressure, improper temperature, and/or the like. Additionally, initially unknown locations of the implanted negligible-sized wireless-tags with sensors may be readily determined upon a given scanning (reading) session; and thus mapped to provide an effective image of the material-of-interest.

Description:
PRIORITY NOTICE 
       [0001]    The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/363,392 filed on Jul. 18, 2016; and the present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/363,413 filed on Jul. 18, 2016, the disclosures of which are both incorporated herein by reference in their entirety. 
         [0002]    The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/363,481 filed on Jul. 18, 2016; and the present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/363,551 filed on Jul. 18, 2016, the disclosures of which are both incorporated herein by reference in their entirety. 
         [0003]    The present patent application is a continuation-in-part (CIP) of U.S. non-provisional patent application Ser. No. 15/418,414 filed on Jan. 27, 2017; wherein this present patent application claims priority to said U.S. non-provisional patent application under 35 U.S.C. §120. The above-identified parent U.S. non-provisional patent application is incorporated herein by reference in their entirety as if fully set forth below. 
         [0004]    The present patent application is a continuation-in-part (CIP) of U.S. non-provisional patent application Ser. No. 15/607,673 filed on May 29, 2017; wherein this present patent application claims priority to said U.S. non-provisional patent application under 35 U.S.C. §120. The above-identified parent U.S. non-provisional patent application is incorporated herein by reference in their entirety as if fully set forth below. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0005]    The present invention relates in general to monitoring states of materials of interest and, more specifically, to monitoring states of materials of interest using wireless sensor tags and where the materials of interest may have uses in dental, medical, and/or construction fields. 
       COPYRIGHT AND TRADEMARK NOTICE 
       [0006]    A portion of the disclosure of this patent application may contain material that is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever. 
         [0007]    Certain marks referenced herein may be common law or registered trademarks of third parties affiliated or unaffiliated with the applicant or the assignee. Use of these marks is by way of example and should not be construed as descriptive or to limit the scope of this invention to material associated only with such marks. 
       BACKGROUND OF THE INVENTION 
       [0008]    Prior art imaging techniques, such as, X-ray, CT-scan, MRI, ultrasound, radar, and/or the like generally involve expensive (expensive to buy, lease, use, train, maintain, etc.), specialized, complicated equipment, and/or equipment that may occupy a relatively large footprint. And in many applications the electromagnetic energy emitted for imaging purposes from some prior art imaging systems may be dangerous or destructive to the object being imaged and thus such imaging must be minimized to prevent problems from overexposure. A prime example of this is the use of X-rays to image hard (dense) structures in biologic samples, such as teeth and bones in vertebrates; where overexposure to X-rays may lead to undesirable mutations and cancers. And even in the case of inanimate objects, such objects may also still be prone to deterioration (e.g., becoming brittle) resulting from overexposure to emitted high energy imaging electromagnetic radiation, such as X-rays. In many instances, if overexposure was not a problem, practitioners would then prefer to utilize such imaging techniques more frequently thus significantly increasing probability of discovering issues earlier in time. In some instances, such as with cancer patients or with pregnant women, use of X-rays is necessarily restricted. 
         [0009]    There is a need in the art for imaging techniques that in comparison to preexisting imaging techniques of X-ray, CT-scan, MRI, ultrasound, radar, and/or the like would be comparatively less expensive to implement; and/or would require a smaller equipment footprint to utilize. Additionally, there is a need in the art for a non-invasive, contactless, imaging techniques that may utilize comparatively less energetic electromagnetic spectra, such as radio waves to communicate information that upon analysis may yield imaging results and other state information of a given material-of-interest to be imaged. 
         [0010]    It is to these ends that the present invention has been developed. Embodiments of the present invention may provide novel ways of analyzing (monitoring and/or tracking) current states, structural integrity, and various qualities of various materials-of-interest; with applications in medical care, dentistry, and construction and engineering without use of preexisting imaging techniques that may use X-ray, CT-scan, MRI, ultrasound, and/or a reliance upon dangerous imaging techniques utilizing ionizing radiation. Examples of materials-of-interest may include, but may not be limited to: dental fillings, root canals, dental crowns, dental sealants and resins, dental and other medical implants, and other structures used in medicine, dentistry and/or construction and/or engineering. 
         [0011]    Using minimization advances in microelectronics and process manufacturing techniques, negligibly-sized micro-sensors may be implanted in the material-of-interest to be analyzed (monitored and/or tracked). In some applications, implantation of such negligibly-sized micro-sensors may be done prior to the given material-of-interest curing and/or hardening, e.g., a dental filling. Using the disclosed imaging technology, subsequent to the completion of such curing or hardening, the current state, e.g., the structural integrity, may be scanned (imaged) to determine possible problems in the material-of-interest such as, but not limited to, possible fracturing, cracking, bending, twisting, excessive pressure, abnormal temperature, foreign materials or liquids penetration, and the like. And such analysis may be done non-invasively, without use of ionizing radiation in some applications, and reading of the implanted negligibly-sized micro-sensors may be remotely measured. Thus, such scanning (i.e., reading or imaging) may be done comparatively much more frequently that would be permitted if the practitioner had to rely upon using X-ray imaging. 
         [0012]    The present invention has also been developed in order to detect specific problems, conditions, and/or substances, such as, but not limited to, biological cells (e.g., foreign cells, abnormal cells, cancerous cells, etc.), infection, fever, inflammation, antigens, antibodies, foreign substances, tissue conditions, ailments, and/or the like. Detection may be a subset of monitoring; wherein devices disclosed herein, as well, as in the accompanying drawings, are capable of monitoring and detection in materials of interest. 
         [0013]    The disclosed imaging techniques may not require a power source in the implanted negligibly-sized micro-sensors. Energy required for the operation of the implanted negligibly-sized micro-sensors may be harvested from external electromagnetic energy sources during the reading (scanning) process. 
         [0014]    Embodiments of the present invention may also establish locations (e.g., positions or coordinates) of wireless-devices with the implanted negligibly-sized micro-sensors. Such location determination may utilize well-known LPS (local positioning systems) techniques, that may involve use of triangulation, trilateration, multilateration, combinations thereof, and the like; as well as involve solving various nonlinear equations using various well-known techniques. Embodiments of the present invention may provide contactless ways of determining real-time locations as well as real-time sensor readings of and from these implanted negligibly-sized wireless-devices with sensors, which over time and over differently placed implanted negligibly-sized wireless-devices with sensors may yield information as to the various current states and changes in state of the given material-of-interest that is being monitored. 
         [0015]    Embodiments of the present invention may also establish locations (e.g., positions or coordinates) of wireless-devices with the implanted negligibly-sized micro-sensors without utilizing LPS (local positioning systems) techniques. 
         [0016]    These wireless-devices (with sensors or without sensors) may be referred to as RFID tags or Near-Field Communication (NFC) devices. Distances (ranges) between these wireless-devices (with sensors or without sensors) and various readers may readily be determined. The reader may emit various electromagnetic (EM) signals and may receive back wireless (returned) electromagnetic signals (e.g., “backscattered”) from the wireless-devices (with sensors or without sensors). And from such returning wireless electromagnetic (EM) signals (such as, but not limited to backscatter electromagnetic signals), distances (ranges) as well as location determination and readings from sensors may then be utilized to analyze various states of the material-of-interest being monitored. 
         [0017]    Localization (location determination) of wireless-devices using well-known LPS (local positioning systems) techniques, that may involve use of triangulation, trilateration, multilateration, combinations thereof, and/or the like is well understood in the relevant art. For example, range measurements between readers and wireless-devices may be based on a number of prior art techniques, among them determining ranges based on phase differences between transmitted and wireless (returned) signals (e.g., “backscattered”), Returned Signal Strength (RSSI), and/or other means. For example, trilateration may be a well-known technique of determining three-dimensional (3D) coordinates of an object using the measured ranges (distances) from that object to three or more other objects with known three-dimensional (3D) coordinates. Triangulation may another well-known technique in this context. 
       BRIEF SUMMARY OF THE INVENTION 
       [0018]    To minimize the limitations in the prior art, and to minimize other limitations that will be apparent upon reading and understanding the present specification, embodiments of the present invention describe devices (tags), systems, and methods to determine structural integrity and other states of materials-of-interest, such as dental fillings, implants, and root canal posts, to name a few, in a non-invasive and contactless way; and using comparatively safe and/or low energy electromagnetic (EM) radiation, such as, but not limited to, radio waves and/or magnetic fields for coupled magnetic induction communication. 
         [0019]    For example, and without limiting the scope of the present invention, in some embodiments, such a system may comprise one or more monitoring-sensor-tags and one or more readers. The one or more monitoring-sensor-tags may be attached to the material-of-interest. The material-of-interest may be selected from a dental-filling, a root-canal-post, a dental-crown, an article implantable within a body of an organism, the article attachable to the body of the organism, specific tissue of the organism, a construction member, and/or the like. The one or more monitoring-sensor-tags may comprise at least one electric circuit, at least one antenna (a first-antenna), and at least one sensor. The at least one electric circuit may be in communication with the at least one antenna (the first-antenna) and the at least one sensor. The one or more readers may comprise one or more second-antennas. The one or more readers using the one or more second-antennas may transmit electromagnetic (EM) radiation of a predetermined characteristic. The first-antenna may receive this electromagnetic (EM) radiation of the predetermined characteristic as an input. This input may cause the at least one electric circuit to take one or more readings from the at least one sensor; and may then transmit the one or more readings using the first-antenna back to the one or more second-antennas. At least one of the second-antennas selected from the one or more second-antennas may then receive the one or more readings. The one or more readers or a device (e.g., a computer) in communication with the one or more readers may then use the one or more readings to determine the current state of the material-of-interest. 
         [0020]    It is an objective of the present invention to provide an imaging system and an imaging method that may be comparatively less expensive to use and implement as compared against traditional X-ray, CT-scan, MRI, ultrasound, radar, or the like imaging systems. 
         [0021]    It is another objective of the present invention to provide an imaging system and an imaging method that may be comparatively easy and simple to use and implement as compared against traditional X-ray, CT-scan, MRI, ultrasound, radar, or the like imaging systems. 
         [0022]    It is another objective of the present invention to provide an imaging system and imaging method that comparatively utilizes as smaller equipment footprint as compared against traditional X-ray, CT-scan, MRI, ultrasound, radar, or the like imaging systems. 
         [0023]    It is another objective of the present invention to provide devices (tags), systems, and methods to determine structural integrity and other states of a given materials-of-interest in a non-invasive and contactless way. 
         [0024]    It is another objective of the present invention to provide devices (tags), systems, and methods to determine structural integrity and other states of a given materials-of-interest using comparatively safe and/or low energy electromagnetic (EM) radiation, such as radio waves, and/or magnetic fields for magnetic induction communication. 
         [0025]    It is another objective of the present invention to provide wireless-tags with sensors (monitoring-sensor-tags) that may be implantable into a given type of material-of-interest as discussed herein. 
         [0026]    It is another objective of the present invention to provide wireless-tags with sensors wherein the sensors may be of different types for measuring different qualities, properties, and/or characteristics. 
         [0027]    It is yet another objective of the present invention to determine locations of wireless-tags with sensors (monitoring-sensor-tags), that may be implantable into a given type of material-of-interest, over time in the same monitoring-sensor-tag and/or as compared against different implanted monitoring-sensor-tags. 
         [0028]    These and other advantages and features of the present invention are described herein with specificity so as to make the present invention understandable to one of ordinary skill in the art, both with respect to how to practice the present invention and how to make the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0029]    Elements in the figures have not necessarily been drawn to scale in order to enhance their clarity and improve understanding of these various elements and embodiments of the invention. Furthermore, elements that are known to be common and well understood to those in the industry are not depicted in order to provide a clear view of the various embodiments of the invention. 
           [0030]      FIG. 1A  may depict a schematic block diagram of a reader. 
           [0031]      FIG. 1B  may depict a schematic block diagram of a monitoring-sensor-tag. 
           [0032]      FIG. 2A  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor. 
           [0033]      FIG. 2B  may depict a schematic block diagram of a monitoring-sensor-tag comprising a resistance-based sensor. 
           [0034]      FIG. 2C  may depict a schematic block diagram of a monitoring-sensor-tag comprising an inductance-based sensor. 
           [0035]      FIG. 2D  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor and a resistance-based-sensor. 
           [0036]      FIG. 2E  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor and an inductance-based-sensor. 
           [0037]      FIG. 2F  may depict a schematic block diagram of a monitoring-sensor-tag comprising a resistance-based sensor and an inductance-based-sensor. 
           [0038]      FIG. 2G  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor, a resistance-based sensor, and an inductance-based-sensor. 
           [0039]      FIG. 3  may be a circuit diagram of a ring oscillator implementing a capacitance measurement circuit. 
           [0040]      FIG. 4A  may be a perspective view of a basic capacitor. 
           [0041]      FIG. 4B  may be a perspective view of a capacitor with substantially parallel regions of a conductive surface of type “A.” 
           [0042]      FIG. 4C  may be a top view of a capacitor; with substantially parallel regions of a conductive surface of type “B”; and with substantially parallel regions of a conductive surface of type “C.” 
           [0043]      FIG. 4D  may be a top view of a capacitor; with regions of a conductive surface of type “D”; and with regions of a conductive surface of type “E.” 
           [0044]      FIG. 4E  may be a top view of a capacitor, with regions of a conductive surface of type “F.” 
           [0045]      FIG. 5A  may be a circuit diagram of a ring oscillator implementing a capacitance measurement circuit. 
           [0046]      FIG. 5B  may be a circuit diagram of a C-MOS pair digital invertor. 
           [0047]      FIG. 6  may be a circuit diagram of a ring oscillator implementing a resistance measurement circuit. 
           [0048]      FIG. 7A  may be a top view of an example of a stress sensor used in some embodiments of the present invention. 
           [0049]      FIG. 7B  may be a top view of an example of a stress sensor used in some embodiments of the present invention. 
           [0050]      FIG. 7C  may be a top view of an example of a stress sensor used in some embodiments of the present invention. 
           [0051]      FIG. 8  may be a diagrammatical top view of a monitoring-sensor-tag&#39;s structure and components, as used in some embodiments of the present invention. 
           [0052]      FIG. 9  may be a diagram of control and status signals, in accordance with some embodiments of the present invention. 
           [0053]      FIG. 10A  may be a diagram of a patient&#39;s tooth with one or more monitoring-sensor-tags placed in dental-filling as a material-of-interest, in accordance with some embodiments of the present invention. 
           [0054]      FIG. 10B  may be a diagram of a patient&#39;s tooth with one or more monitoring-sensor-tags placed in: a root-canal-cavity, in a root-canal-post, and/or in a dental-crown; in accordance with some embodiments of the present invention. 
           [0055]      FIG. 10C  may be a diagram of a patient&#39;s tooth dental-implant with one or more monitoring-sensor-tags, in accordance with some embodiments of the present invention. 
           [0056]      FIG. 10D  may be a diagram of a first-sensor-tag and a second-sensor-tag arranged in a material-of-interest with an initial predetermined spacing between the first-sensor-tag and the second-sensor-tag in this material-of-interest. 
           [0057]      FIG. 11A  may be a diagrammatical top view of a reader-and-calibration-member, in accordance with some embodiments of the present invention. 
           [0058]      FIG. 11B  may be a diagrammatical top view of a reader-and-calibration-member, in accordance with some embodiments of the present invention. 
           [0059]      FIG. 11C  may be a diagrammatical top view of a reader-and-calibration-member with an antenna interface, in accordance with some embodiments of the present invention. 
           [0060]      FIG. 12  may be a diagrammatical side view (or a top view) of a position-reference-member, in accordance with the present invention. 
           [0061]      FIG. 13A  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags that may be in and/or on a patient; wherein the system comprises a translating-scan-member that may translate along a predetermined path of motion. 
           [0062]      FIG. 13B  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags that may be in and/or on a patient; wherein the system comprise a reader-housing-member with one or more readers that may communicate with the one or monitoring-sensor-tags. 
           [0063]      FIG. 13C  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags that may be in and/or on a patient; wherein the system comprises a translating-scan-member that may translate along a predetermined path of motion. 
           [0064]      FIG. 14A  may be a schematic view of a single monitoring-sensor-tag and a plurality of readers that may communicate (wirelessly) with the single monitoring-sensor-tag. 
           [0065]      FIG. 14B  may be a schematic view of a single monitoring-sensor-tag and a single reader; wherein the single reader may translate with respect to the single monitoring-sensor-tag; and wherein the single reader and the single monitoring-sensor-tag may be in wireless communication. 
           [0066]      FIG. 15  may depict a flow diagram illustrating steps in a method for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor tag using one or more readers. 
           [0067]      FIG. 16  may depict a flow diagram illustrating a method for calibrating a system (shown in  FIG. 18 ) based on one or more reference-sensor-tags. 
           [0068]      FIG. 17  may depict a flow diagram for determining location of one or more monitoring-sensor-tags associated with a material-of-interest. 
           [0069]      FIG. 18  may depict a block diagram of a device, a reader, a processor, memory, a display, a position-reference-member, and a material-of-interest with one or more monitoring-sensor-tags. 
           [0070]      FIG. 19A  may depict a graph showing a physical relationship between complex permittivity and changes in frequency. 
           [0071]      FIG. 19B  may depict a perspective view of a capacitor connected to an alternating current (AC) voltage source. 
           [0072]      FIG. 19C  may depict a schematic view of a capacitor representative circuit. 
           [0073]      FIG. 19D  may depict a schematic view of a capacitor representative circuit connected to an alternating current (AC) voltage source. 
           [0074]      FIG. 19E  may show how complex permittivity of a given material (including biologic materials) may vary according to changes in excitation source(s), as well as changes in frequency. 
           [0075]      FIG. 19F  may be a view of a capacitor connected to an alternating current (AC) voltage source, wherein a dielectric material, disposed between opposing capacitor plates of the capacitor, may be exposed to one or more types of excitation sources, of predetermined characteristics. 
           [0076]      FIG. 20A  may depict a schematic view of a complex-monitoring-sensor-tag. 
           [0077]      FIG. 20B  may depict a schematic block diagram of a complex-monitoring-sensor-tag, similar to that as shown in  FIG. 20A , but wherein in  FIG. 20B , the complex-monitoring-sensor-tag may further comprise an array-of-excitation-sources, that may comprise one or more excitation sources. 
           [0078]      FIG. 21A  may depict a schematic view of an example of measuring complex impedance using an alternating AC voltage source. 
           [0079]      FIG. 21B  may depict a schematic view of an example of measuring complex impedance using an alternating AC current source. 
           [0080]      FIG. 22A  may depict a schematic view of an example of a two electrode electrochemical impedance spectroscopy (EIS) application. 
           [0081]      FIG. 22B  may depict a schematic view of an example of a four electrode electrochemical impedance spectroscopy (EIS) application. 
           [0082]      FIG. 23A  may depict a schematic view of an example of a four terminal (electrode) portion of a complex impedance sensor. 
           [0083]      FIG. 23B  may depict a schematic view of an example of a four terminal (electrode) portion of a complex impedance sensor. 
           [0084]      FIG. 23C  may depict a schematic view of an example of a four terminal (electrode) portion of a complex impedance sensor. 
           [0085]      FIG. 23D  may be a view of two different opposed terminal probes; of regions of a conductive surface of type “K” mounted to a given material-of-interest, with different IR lights sources disposed between the probes and capable of emitting different IR light to the given material-of-interest. 
           [0086]      FIG. 24A  may depict a system for monitoring and/or tracking, non-invasively, a state of skin or of tissue, using a cast-or-bandage with lattice-of-sensors that may be in communication with a reader-and-calibration-member and/or with a device (e.g., a mobile computer). 
           [0087]      FIG. 24B  may depict a schematic view of lattice-of-sensors. 
           [0088]      FIG. 24C  may depict a system for monitoring and/or tracking, non-invasively, a state of breast skin or of breast tissue, using an article-in-lattice-contact (e.g., a bra) with lattice-of-sensors that may be in communication with a reader-and-calibration-member and/or with a device (e.g., a mobile computer). 
           [0089]      FIG. 24D  may depict a portion of an article-in-lattice-contact (e.g., a bra) or a portion of a cast-or-bandage (e.g., a cast or bandage), showing lattice-of-sensors on the interior-surface. 
           [0090]      FIG. 24E  may depict a diagram showing at least one lattice-of-sensors that may be imbedded within a given implant. 
           [0091]      FIG. 24F  may depict a diagram showing at least one lattice-of-sensors that may be mounted on (attached to) an external surface of a given implant. 
           [0092]      FIG. 25A  may depict a schematic view of a complex-monitoring-sensor-tag, showing details of a complex-impedance-measurement-circuit. 
           [0093]      FIG. 25B  may depict a schematic view of a complex-monitoring-sensor-tag, showing details of a complex-impedance-measurement-circuit. 
           [0094]      FIG. 25C  may depict a schematic view of a complex-monitoring-sensor-tag, showing details of a complex-impedance-measurement-circuit. 
           [0095]      FIG. 25D  may depict additional details of the complex-monitoring-sensor-tag of  FIG. 20B , in a schematic block diagram. 
           [0096]      FIG. 26  may depict may depict a perspective view of a portion of a material-of-interest with monitoring-sensor-tags. 
           [0097]      FIG. 27A  may depict a top view of an imaging-device rolling along an exterior surface of a material-of-interest. 
           [0098]      FIG. 27B  may depict a top view of a reader-assembly. 
           [0099]      FIG. 27C  may depict an orthogonal view (e.g., a side view) of the reader-assembly of  FIG. 27B . 
           [0100]      FIG. 28  may depict a perspective view of a portion of a material-of-interest with monitoring-sensor-tags; and may also depict an imaging-device, a position-reference-member, and a predetermined coordinate system. 
           [0101]      FIG. 29A  may depict a schematic view of a position-reference-member with a transmitter. 
           [0102]      FIG. 29B  may depict a schematic view of the transmitter of  FIG. 29A  connected to a device, such as a computer. 
           [0103]      FIG. 30  may depict a perspective view of a portion of a material-of-interest: with reader-and-calibration-members, a position-reference-member, monitoring-sensor-tags, and a predetermined coordinate system. 
           [0104]      FIG. 31  may depict possible wireless communication pathways for a transmitter. 
           [0105]      FIG. 32  may depict a flow diagram illustrating steps in a method for non-invasive monitoring of a material-of-interest with one or more complex-monitoring-sensor-tag(s) employing electrochemical impedance spectroscopy (EIS). 
       
    
    
     REFERENCE NUMERAL SCHEDULE 
       [0000]    
       
           100  reader  100   
           110  antenna  110  (second-antenna  110 ) 
           120  monitoring-sensor-tag  120   
           130  antenna  130  (first-antenna  130 ) 
           140  electric circuit  140   
           202  capacitive-based sensor  202   
           203  resistance-based sensor  203   
           204  processing circuitry  204   
           205  capacitance measurement circuit  205   
           206  resistance measurement circuit  206   
           207  wireless-receiver-and-transmitter  207   
           208  inductance-based-sensor  208   
           209  inductance measurement circuit  209   
           300  load capacitor  300   
           310  digital inventor  310  (e.g., a C-MOS pair  310 ) 
           340  capacitive-based sensor  340   
           350  ring oscillator  350   
           400  plate  400   
           401  dielectric material  401   
           402  conductive surface type “A”  402   
           403  substrate  403   
           404  conductive surface type “B”  404   
           405  conductive surface type “C”  405   
           406  conductive surface type “D”  406   
           407  conductive surface type “E”  407   
           408  conductive surface type “F”  408   
           500  ring oscillator  500   
           501  switch  501   
           502  P-MOS transistor  502   
           503  N-MOS transistor  503   
           600  ring oscillator  600   
           601  load resistor  601   
           602  strain-influenced resistor  602   
           700  strain-influenced resistor  700   
           701  thin-film-coating  701   
           702  substrate  702   
           703  spiral-formed-electric-conductor  703   
           801  sensor-portion  801   
           802  processing-portion  802   
           930  CLOCK  930   
           931  RESTART_COUNT signal  931   
           932  COUNTER  932   
           933  COUNTER_OVERFLOW signal  933   
           934  zero value  934   
           935  0-to-1 transition of Pulse of Counter Overflow signal  935   
           936  1-to-0 transition of Pulse of Counter Overflow signal  936   
           937  maximal value  937   
           938  Pulse of RESTART_COUNT signal  938   
           1000  tooth  1000   
           1001  dental-filling  1001   
           1002  gum  1002   
           1003  root-canal-cavity  1003   
           1004  root-canal-post  1004   
           1005  dental-crown  1005   
           1006  standalone-strain-sensor  1006   
           1007  dental-implant  1007   
           1008  implant-post  1008   
           1020  first-sensor-tag  1020   
           1021  second-sensor-tag  1021   
           1023  lattice-of-sensors  1023   
           1025  initial predetermined spacing  1025   
           1026  sensor-spacing  1026   
           1028  material-of-interest  1028   
           1102  reference-sensor-tags  1102   
           1107  reference-housing-member  1107   
           1108  reader-housing-member  1108   
           1109  reader-and-calibration-member  1109   
           1110  member-separation-distance  1110   
           1111  reader-tag-separation-distance  1111   
           1112  reader-antenna-tag-separation-distance  1112   
           1113  reader-antenna-tag-separation-distance  1113   
           1115  antenna-interface  1115   
           1203  position-reference-tag  1203   
           1204  position-reference-member  1204   
           1320  Imaginary x-axis  1320   
           1321  Imaginary y-axis  1321   
           1322  Imaginary z-axis  1322   
           1325  origin  1325   
           1326  translating-scan-member  1326   
           1327  patient-fixation-member  1327   
           1328  patient  1328   
           1329  support  1329   
           1400  direction-of-motion  1400   
           1500  method  1500   
           1530  calibrate readers step  1530   
           1531  determine location of readers step  1531   
           1532  reader interrogation of monitoring-sensor-tags step  1532   
           1533  authentication step  1533   
           1534  determine location of monitoring-sensor-tags step  1534   
           1535  reader instructs monitoring-sensor-tags step  1535   
           1535   a  reader instructs monitoring-sensor-tags step  1535   a    
           1536  reader transmit “restart counting” command step  1536   
           1537  determine if additional measurements to be taken step  1537   
           1538  determine if reader location to be re-determined step  1538   
           1539  determine if different measurement types to be taken step  1539   
           1540  transmit received monitoring-sensor-tag transmission step  1540   
           1600  method  1600   
           1680  choose set of calibration reference-sensor-tags step  1680   
           1681  select particular calibration method and settings step  1681   
           1682  perform calibration reference-sensor-tags measurements step  1682   
           1683  process calibration reference-sensor-tags measurements step  1683   
           1700  method  1700   
           1772  measuring ranges of monitoring-sensor tags step  1772   
           1773  applying calibration-based corrections step  1773   
           1777  process results step  1777   
           1800  system  1800   
           1801  processor  1801   
           1803  memory  1803   
           1805  display  1805   
           1807  device  1807   
           1828  material-of-interest  1828   
           1901  real part of complex permittivity  1901   
           1902  imaginary part of complex permittivity  1902   
           1905  capacitor  1905   
           1906  voltage source  1906   
           1907  resistor  1907   
           1908  capacitor  1908   
           1909  representative circuit  1909   
           1910  current  1910   
           1911  graph of real part of complex permittivity  1911   
           1912  graph of imaginary part of complex permittivity  1912   
           1913  graph real part of complex permittivity  1913   
           1914  graph of imaginary part of complex permittivity  1914   
           1915  graph of real part of complex permittivity  1915   
           1916  graph of imaginary part of complex permittivity  1916   
           1917  infrared (IR) light source  1917   
           1918  LED light source  1918   
           1919  ultraviolet (UV) light source  1919   
           1920  sonic or ultrasonic sound source  1920   
           1921  array-of-excitation-sources  1921   
           2010  complex-impedance-sensor  2010   
           2011  complex-impedance-measurement-circuit  2011   
           2020  complex-monitoring-sensor-tag  2020   
           2101  load  2101   
           2103  resistor  2103   
           2104  point  2104   
           2105  point  2105   
           2106  current source  2106   
           2201  material-of-interest  2201   
           2203  electrode  2203   
           2204  electrode  2204   
           2205  voltage meter  2205   
           2309  conductive surface type “G”  2309   
           2310  conductive surface type “G”  2310   
           2311  conductive surface of type “H”  2311   
           2312  conductive surface of type “H”  2312   
           2313  conductive surface of type “I”  2313   
           2314  conductive surface of type “I”  2314   
           2315  conductive surface of type “J”  2315   
           2316  conductive surface of type “J”  2316   
           2317  conductive surface of type “K”  2317   
           2318  infrared (IR) light source of type “A”  2318   
           2319  infrared (IR) light source of type “B”  2319   
           2401  cast-or-bandage  2401   
           2402  interior-surface  2402   
           2406  first-sensor-type  2406   
           2407  second-sensor-type  2407   
           2420  first-sensor-tag  2420   
           2421  second-sensor-tag  2421   
           2423  lattice-of-sensors  2423   
           2426  sensor-spacing  2426   
           2430  article-in-lattice-contact  2430   
           2431  implant  2431   
           2511  analyzer  2511   
           2512  variable-frequency-AC-source  2512   
           2513  frequency-divider  2513   
           2514  variable resistor  2514   
           2687  material-of-interest  2687   
           2688  section  2688   
           2709  reader-assembly  2709   
           2711  frame-member  2711   
           2712  imaging-device  2712   
           2720  wheel  2720   
           2722  axle  2722   
           2724  frame  2724   
           2726  handle  2726   
           2728  spring  2728   
           2730  base  2730   
           2820  x-axis  2820   
           2821  y-axis  2821   
           2822  z-axis  2822   
           2825  origin  2825   
           2904  position-reference-member  2904   
           2926  transmitter  2926   
           3101  internet-or-WAN-or-LAN  3101   
           3103  server  3103   
           3105  remote-computing-device  3105   
           3201  step of selecting frequency point to measure complex impedance  3201   
           3202  step of determining if one or more excitation-sources are to be enabled  3202   
           3203  step of choosing and enabling one or more excitation-sources  3203   
           3204  step of obtaining measurement of complex impedance of material-of-interest  3204   
           3205  step of determining if more measurements of material-of-interest to be taken  3205   
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0298]    In the following discussion that addresses a number of embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part thereof, where depictions are made, by way of illustration, of specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the invention. 
         [0299]      FIG. 1A  may depict a schematic block diagram of a reader  100 . In some embodiments, reader  100  may comprise antenna  110 . In some embodiments, reader  100  may comprise at least one antenna  110 . In some embodiments, reader  100  may comprise one or more antennas  110 . 
         [0300]      FIG. 1B  may depict a schematic block diagram of a monitoring-sensor-tag  120 . In some embodiments, monitoring-sensor-tag  120  may comprise at least one electric circuit  140 . In some embodiments, monitoring-sensor-tag  120  may comprise at least one antenna  130  in communication with the at least one electric circuit  140 . In some embodiments, at least one electric circuit  140  may be in communication with at least one sensor. In some embodiments, monitoring-sensor-tag  120  may comprise the at least one sensor. In some embodiments, at least one electric circuit  140  may comprise the at least one sensor. 
         [0301]    In some embodiments, at least one electric circuit  140  may be an integrated circuit. In some embodiments, the at least one sensor (e.g.,  202 ,  203 , and/or other sensors discussed herein) may be located inside of and integral with such an integrated circuit and in electrical communication with the integrated circuit. In some embodiments, the at least one sensor (e.g.,  202 ,  203 ,  1006 , and/or other sensors discussed herein) may be located outside of such an integrated circuit and in electrical communication with the integrated circuit. 
         [0302]    In some embodiments, a given monitoring-sensor-tag  120  may be a wireless sensor tag. In some embodiments, a given monitoring-sensor-tag  120  may be one or more of: a RFID (radio frequency identification) sensor tag; a NFC (near field communication) sensor tag; a backscatter sensor tag; and/or magnetic inductive activated sensor tag. 
         [0303]    In some embodiments, a given monitoring-sensor-tag  120  may communicate with a given reader  100 . In some embodiments, such communication may be wireless. In some embodiments, such wireless communication may be via a predetermined wavelength or via predetermined wavelengths of electromagnetic (EM) radiation. For example, and without limiting the scope of the present invention, such a wavelength may be wavelengths associated with radio waves. For example, and without limiting the scope of the present invention, a given reader  100  may “interrogate” monitoring-sensor-tags  120  at a number of predetermined frequencies. 
         [0304]    In some embodiments, upon at least one antenna  130  receiving electromagnetic (EM) radiation of a predetermined characteristic as an input from at least one antenna  110 , this input may cause at least one electric circuit  140  to take one or more readings from the at least one sensor and to then transmit such one or more readings using at least one antenna  130 . Then, at least one antenna  110  may receive these one or more readings being broadcast from at least one antenna  130 . Hence, reader  100  may be “reading” from (i.e., scanning for) signals broadcast from a given monitoring-sensor-tag  120 . 
         [0305]    In some embodiments, when the at least one electric circuit  140  may cause the at least one antenna  130  to transmit the one or more readings, the at least one electric circuit  140  may also cause the at least one antenna  130  to transmit “additional information.” In some embodiments, this “additional information” may comprise one or more of: identification information for a given monitoring-sensor-tag  120  that is transmitting (e.g., an ID for each monitoring-sensor-tag  120  that is transmitting); model number for the given monitoring-sensor-tag  120  that is transmitting; serial number for the given monitoring-sensor-tag  120  that is transmitting; manufacturer of the given monitoring-sensor-tag  120  that is transmitting; year of manufacture of the given monitoring-sensor-tag  120  that is transmitting; or a request for a security code associated with that given monitoring-sensor-tag  120  that is transmitting; a cyclic redundancy check code for the information that the given monitoring-sensor-tag  120  that is transmitting; a parity check code for information that the given monitoring-sensor-tag  120  that is transmitting; and receipt of a disable instruction for the given monitoring-sensor-tag  120  that is transmitting; wherein the given monitoring-sensor-tag  120  that is transmitting is selected from the one or more monitoring-sensor-tags  120 . 
         [0306]    In some embodiments, monitoring-sensor-tag  120  may be passive and receive power wirelessly transmitted from a given reader  100 . That is, electrical power required to operate a given monitoring-sensor-tag  120  may be provided wirelessly from at least one antenna  110  from a given reader  100  that may be broadcasting and sufficiently close to at least one antenna  130  of given monitoring-sensor-tag  120 . 
         [0307]    In some embodiments, at least one of the one or more monitoring-sensor-tags  120  may be from substantially six inches to substantially 1.0 micrometer in a largest dimension of the at least one of the one or more monitoring-sensor-tags  120 . In some embodiments, “substantially” in this context may mean plus or minus 10% of the given unit of measurement; i.e., plus or minus 10% of an inch and plus or minus 10% of a micrometer. In application, the size of a given monitoring-sensor-tag  120  may be negligible with respect to any impact the given monitoring-sensor-tag  120  may have on the associated material-of-interest; i.e., the sizes of the utilized monitoring-sensor-tags  120  may not negatively affect the associated material-of-interest. 
         [0308]    In some embodiments, each monitoring-sensor-tag  120  may be attached to a given material-of-interest. Note, such materials-of-interest are not shown in  FIG. 1A  and in  FIG. 1B . In some embodiments, a given material-of-interest may be selected from: a dental-filling  1001  (see e.g.,  FIG. 10A ), a root-canal-post  1004  (see e.g.,  FIG. 10B ), a root-canal-cavity  1003  (see e.g.,  FIG. 10B ), a dental-crown  1005  (see e.g.,  FIG. 10B ), a dental-implant  1007  (see e.g.,  FIG. 10C ), an article implantable within a body of an organism, the article attachable to the body of the organism, specific tissue of the organism, a construction member, and/or the like. See also  FIG. 10D  for material-of-interest  1028 , which in some embodiments may be any of the above identified given materials-of-interest. See also  FIG. 13C  showing monitoring-sensor-tag  120  located within a leg of a patient  1328 ; wherein in that example a portion of the leg (e.g., tissue, bone, an implant, or the like) may be given material-of-interest. See also  FIG. 18  for material-of-interest  1828 , which in some embodiments may be any of the above identified given materials-of-interest. 
         [0309]    In some embodiments, the given material-of-interest may be an article. In some embodiments, the article may be selected from: a medical device; a tissue graft; a bone graft; an artificial tissue; a bolus with time-release medication; a medication; and/or the like. In some embodiments, the medical device may be selected from one or more of: a dental-implant  1007 , an implantable device, an implantable organ (e.g., may include from a cadaver), implantable tissue (e.g., may include from a cadaver), an artificial organ, artificial tissue, an artificial joint, an artificial limb, an artificial valve, a suture, and/or the like. 
         [0310]    In some embodiments, the construction member (of the given material-of-interest) may be selected from one or more of: concrete; cement; plaster; mortar; resin; brick; block; drywall; particle board; plywood; wood framing member (e.g., a stud); posts; beams; girders; engineered structural members; and/or the like. 
         [0311]    In some embodiments, one or more monitoring-sensor-tags  120  being “attached to” the given material-of-interest, at an initial time of “attachment,” may comprise one or more of the following locations: on a surface of the given material-of-interest; within the given material-of-interest; partially on the surface of the given material-of-interest and partially within the given material-of-interest; and/or the like. In some embodiments, the one or more monitoring-sensor-tags  120  may be immersed entirely within the material-of-interest. In some embodiments, the one or more monitoring-sensor-tags  120  may be immersed at least partially within the material-of-interest. That is, in some embodiments, “attached to” may comprise “immersion.” In some embodiments, one or more monitoring-sensor-tags  120  may associate with the given material-of-interest; such as, but not limited to, translating with the given material-of-interest. 
         [0312]    In some embodiments, an importance of attaching one or more monitoring-sensor-tags  120  with the given material-of-interest, may be that the at least one sensor of a given monitoring-sensor-tag  120  may then convey state information from readings of that at least one given sensor. That is, by using the monitoring-sensor-tags  120  attached to the given material-of-interest, information (e.g., various states) of the given material-of-interest may be monitored and/or tracked. In some embodiments, such monitoring and/or tracking may be accomplished with using radio waves as opposed to ionizing imaging radiation like x-rays; which may provide for increased safety to patients  1328  when the given material-of-interest is associated with a given patient  1328 . Additionally, because of this, more frequent monitoring and/or tracking of the given material-of-interest may be utilized, resulting in increased efficacy and minimization of problems that may arise to due to infrequent monitoring, as there may be minimal need to minimize patient  1328  exposure to ionizing imaging radiation since embodiments of the present invention may communicate over radio waves between monitoring-sensor-tags  120  and various readers  100 . 
         [0313]    For example, and without limiting the scope of the present invention, in some embodiments, such state information of the given material-of-interest that may be monitored and/or tracked by using one or more monitoring-sensor-tags  120  attached to the given material-of-interest may be one or more of: structural integrity of a current state of the material-of-interest; structural integrity changes of the material-of-interest; pressure received at the material-of-interest; force received at the material-of-interest; stress received at the material-of-interest; torsion received at the material-of-interest; deformation received at the material-of-interest; temperature at some portion of the material-of-interest; positional changes of a given monitoring-sensor-tag  120  attached to the material-of-interest with respect to position of another monitoring-sensor-tag  120  attached to the material-of-interest, wherein the given monitoring-sensor-tag  120  and the other monitoring-sensor-tag are  120  selected from the one or more monitoring-sensor-tags  120  attached to the material-of-interest; or positional changes of at least one monitoring-sensor-tag  120  attached to the material-of-interest with respect to time, wherein the at least one monitoring-sensor-tag  120  is selected from the one or more monitoring-sensor-tags  120 . 
         [0314]      FIG. 2A  may depict a schematic block diagram of monitoring-sensor-tag  120  comprising a capacitive-based sensor  202 . In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , capacitance measurement circuit  205 , and capacitive-based sensor  202 . In some embodiments, processing circuitry  204  may be in communication with capacitance measurement circuit  205 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, capacitance measurement circuit  205  may be in communication with capacitive-based sensor  202 . 
         [0315]    In some embodiments, capacitance measurement circuit  205  may measure the capacitance of capacitive-based sensor  202  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control capacitance measurement circuit  205  and process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2A . 
         [0316]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204  and capacitance measurement circuit  205 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , and capacitive-based sensor  202 . 
         [0317]      FIG. 2B  may depict a schematic block diagram of monitoring-sensor-tag  120  comprising a resistance-based sensor  203 . In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , resistance measurement circuit  206 , and resistance-based sensor  203 . In some embodiments, processing circuitry  204  may be in communication with resistance measurement circuit  206 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, resistance measurement circuit  206  may be in communication with resistance-based sensor  203 . 
         [0318]    In some embodiments, resistance measurement circuit  206  may measure the resistance of resistance-based sensor  203  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control resistance measurement circuit  206  and process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2B . 
         [0319]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204  and resistance measurement circuit  206 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , resistance measurement circuit  206 , and resistance-based sensor  203 . 
         [0320]      FIG. 2C  may depict a schematic block diagram of monitoring-sensor-tag  120  comprising an inductance-based-sensor  208 . In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , inductance measurement circuit  209 , and inductance-based-sensor  208 . In some embodiments, processing circuitry  204  may be in communication with inductance measurement circuit  209 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, inductance measurement circuit  209  may be in communication with inductance-based-sensor  208 . 
         [0321]    In some embodiments, inductance measurement circuit  209  may measure the inductance of inductance-based-sensor  208  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control inductance measurement circuit  209  and process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2C . 
         [0322]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204  and inductance measurement circuit  209 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , inductance measurement circuit  209 , and inductance-based-sensor  208 . 
         [0323]      FIG. 2D  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor  202  and a resistance-based-sensor  203 . In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , resistance measurement circuit  206 , and resistance-based sensor  203 . In some embodiments, processing circuitry  204  may be in communication with capacitance measurement circuit  205 . In some embodiments, processing circuitry  204  may be in communication with resistance measurement circuit  206 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, capacitance measurement circuit  205  may be in communication with capacitive-based sensor  202 . In some embodiments, resistance measurement circuit  206  may be in communication with resistance-based sensor  203 . 
         [0324]    In some embodiments, capacitance measurement circuit  205  may measure the capacitance of capacitive-based sensor  202  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, resistance measurement circuit  206  may measure the resistance of resistance-based sensor  203  to quantify another current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control capacitance measurement circuit  205  and may control resistance measurement circuit  206  and process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2D . 
         [0325]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , and resistance measurement circuit  206 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , resistance measurement circuit  206 , and resistance-based sensor  203 . 
         [0326]      FIG. 2E  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor  202  and an inductance-based-sensor  208 . In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , inductance measurement circuit  209 , and inductance-based-sensor  208 . In some embodiments, processing circuitry  204  may be in communication with capacitance measurement circuit  205 . In some embodiments, processing circuitry  204  may be in communication with inductance measurement circuit  209 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, capacitance measurement circuit  205  may be in communication with capacitive-based sensor  202 . In some embodiments, inductance measurement circuit  209  may be in communication with inductance-based-sensor  208 . 
         [0327]    In some embodiments, capacitance measurement circuit  205  may measure the capacitance of capacitive-based sensor  202  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, inductance measurement circuit  209  may measure the inductance of inductance-based-sensor  208  to quantify another current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control capacitance measurement circuit  205  and may control inductance measurement circuit  209  and process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2E . 
         [0328]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , and inductance measurement circuit  209 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , inductance measurement circuit  209 , and inductance-based-sensor  208 . 
         [0329]      FIG. 2F  may depict a schematic block diagram of a monitoring-sensor-tag comprising a resistance-based sensor  203  and an inductance-based-sensor  208 . 
         [0330]    In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , resistance measurement circuit  206 , resistance-based sensor  203 , inductance measurement circuit  209 , and inductance-based-sensor  208 . In some embodiments, processing circuitry  204  may be in communication with resistance measurement circuit  206 . In some embodiments, processing circuitry  204  may be in communication with inductance measurement circuit  209 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, resistance measurement circuit  206  may be in communication with resistance-based sensor  203 . In some embodiments, inductance measurement circuit  209  may be in communication with inductance-based-sensor  208 . 
         [0331]    In some embodiments, resistance measurement circuit  206  may measure the resistance of resistance-based sensor  203  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, inductance measurement circuit  209  may measure the inductance of inductance-based-sensor  208  to quantify another current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control resistance measurement circuit  206  and may control inductance measurement circuit  209  and may process the one or more readings (the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2F . 
         [0332]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , resistance measurement circuit  206 , and inductance measurement circuit  209 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , resistance measurement circuit  206 , resistance-based sensor  203 , inductance measurement circuit  209 , and inductance-based-sensor  208 . 
         [0333]      FIG. 2G  may depict a schematic block diagram of a monitoring-sensor-tag comprising a capacitive-based sensor  202 , a resistance-based sensor  203 , and an inductance-based-sensor  208 . 
         [0334]    In some embodiments, a given monitoring-sensor-tag  120  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , resistance measurement circuit  206 , resistance-based sensor  203 , inductance measurement circuit  209 , and inductance-based-sensor  208 . In some embodiments, processing circuitry  204  may be in communication with capacitance measurement circuit  205 . In some embodiments, processing circuitry  204  may be in communication with resistance measurement circuit  206 . In some embodiments, processing circuitry  204  may be in communication with inductance measurement circuit  209 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, capacitance measurement circuit  205  may be in communication with capacitive-based sensor  202 . In some embodiments, resistance measurement circuit  206  may be in communication with resistance-based sensor  203 . In some embodiments, inductance measurement circuit  209  may be in communication with inductance-based-sensor  208 . 
         [0335]    In some embodiments, capacitance measurement circuit  205  may measure the capacitance of capacitive-based sensor  202  to quantify a current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, resistance measurement circuit  206  may measure the resistance of resistance-based sensor  203  to quantify another current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, inductance measurement circuit  209  may measure the inductance of inductance-based-sensor  208  to quantify yet another current state reading of material-of-interest that monitoring-sensor-tag  120  may be attached to. In some embodiments, processing circuitry  204  may control capacitance measurement circuit  205 , may control resistance measurement circuit  206 , and may control inductance measurement circuit  209 . In some embodiments, processing circuitry  204  may process the one or more readings (i.e., the obtained results) for radio-frequency transmission (or for other electromagnetic transmission). In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 2G . 
         [0336]    In some embodiments, at least one antenna  130  (of monitoring-sensor-tag  120 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , resistance measurement circuit  206 , and inductance measurement circuit  209 . In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise processing circuitry  204 , capacitance measurement circuit  205 , capacitive-based sensor  202 , resistance measurement circuit  206 , resistance-based sensor  203 , inductance measurement circuit  209 , and inductance-based-sensor  208 . 
         [0337]    As noted above in the  FIG. 1B  discussion of monitoring-sensor-tag  120 , monitoring-sensor-tag  120  may comprise the at least one sensor. In some embodiments, the at least one sensor may be selected from one or more of: capacitive-based sensor  202 , resistance-based sensor  203 , and/or inductance-based-sensor  208 . See e.g.,  FIG. 2A  through and including  FIG. 2G . 
         [0338]    As noted above in the  FIG. 1B  discussion of monitoring-sensor-tag  120 , at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may comprise the at least one sensor. In some embodiments, the at least one sensor may be selected from one or more of: capacitive-based sensor  202 , resistance-based sensor  203 , and/or inductance-based-sensor  208 . See e.g.,  FIG. 2A  through and including  FIG. 2G . 
         [0339]    In some embodiments, at least one electric circuit  140  (of monitoring-sensor-tag  120 ) may be attached to and in communication with the at least one sensor, such as, but not limited to: spiral-formed-electric-conductor  703  (see e.g.,  FIG. 7C ); standalone-strain-sensor  1006  (see e.g.,  FIG. 10B ,  FIG. 10C , and  FIG. 18 ); and lattice-of-sensors  1023  (see e.g.,  FIG. 10D ). 
         [0340]    In some embodiments, the one or more readings taken from the at least one sensor may be readings of one or more of: inductance from one or more inductance-based-sensors  208 ; capacitance from one or more capacitive-based sensors  202 ; and/or resistance from one or more resistance-based sensors  203 . See e.g.,  FIG. 2A  through and including  FIG. 2G . In some embodiments, such one or more readings of current values, over time, of one or more of inductance, capacitance, or resistance may determine changes in such properties. In some embodiments, initial current value readings may function as baseline readings that future current value readings may be monitored against to determine changes. 
         [0341]    In some embodiments, these one or more readings may provide status information to determine one or more of: structural integrity of a current state of the material-of-interest; structural integrity changes of the material-of-interest; pressure received at the material-of-interest; force received at the material-of-interest; stress received at the material-of-interest; torsion received at the material-of-interest; deformation received at the material-of-interest; temperature at some portion of the material-of-interest; positional changes of a given monitoring-sensor-tag  120  attached to the material-of-interest with respect to position of another monitoring-sensor-tag  120  attached to the material-of-interest, wherein the given monitoring-sensor-tag  120  and the other monitoring-sensor-tag are  120  selected from the one or more monitoring-sensor-tags  120  attached to the material-of-interest; or positional changes of at least one monitoring-sensor-tag  120  attached to the material-of-interest with respect to time, wherein the at least one monitoring-sensor-tag  120  is selected from the one or more monitoring-sensor-tags  120 . In some embodiments, readings from one or more of capacitive-based sensor  202 , resistance-based sensor  203 , and/or inductance-based-sensor  208  may yield such current status information as noted above. 
         [0342]    In some embodiments, structural integrity changes of the material-of-interest may comprise monitoring for liquid penetration into the given material-of-interest. In some embodiments, liquid as used herein may comprise viscous fluids, slurries, and/or slow flow films. In some embodiments, liquid as used herein may comprise viscous fluids, slurries, and/or slow flow films that may harden and/or become cured into a hardened state (with no to minimal flow). In some embodiments, structural integrity changes of the material-of-interest may comprise monitoring for liquid penetration to the at least one sensors (e.g.,  202  and/or  203 ) located within the given material-of-interest. For example, and without limiting the scope of the present invention, the at least one sensors (e.g.,  202 ,  203 , and/or  1006 ) may monitor for liquid penetration into filling  1001 , see e.g.,  FIG. 10A ; for liquid penetration beneath dental-crowns  1005 , see e.g.,  FIG. 10B ; for liquid penetration into root-canal-cavity  1003 , see e.g.,  FIG. 10B ; or monitor for liquid penetration into other materials-of-interest. Such liquid penetration may indicate an increased likelihood of infection and/or of structural integrity failures and/or detachment of the given material-of-interest (e.g., detachment of: dental-filling  1001 , dental-crown  1005 , root-canal-post  1004 , and/or dental-implant  1007 ). In some embodiments, such at least one sensors (e.g.,  202 ,  203 , and/or  1006 ) may monitor for liquid penetration at the at least one sensors (e.g.,  202 ,  203 , and/or  1006 ), in at least some portion of the given material-of-interest, and/or within hollow space within the given material-of-interest. In some embodiments, such at least one sensors (e.g.,  202 ,  203 , and/or  1006 ) may monitor for liquid penetration without the at least one sensors (e.g.,  202 ,  203 , and/or  1006 ) coming in physical contact with the liquid. 
         [0343]    It should be appreciated by those of ordinary skill in the relevant art that capacitive-based sensor  202  and capacitance measurement circuits  205  may be used to implement configurations depicted in  FIG. 2A ,  FIG. 2D ,  FIG. 2E , and/or  FIG. 2G  to quantify, measure, track, monitor, and/or analyze various states and changes in states of materials-of-interest with one or more monitoring-sensor-tag  120  processing the one or more reading originating from such capacitive-based sensor  202 . 
         [0344]      FIG. 3  may be a circuit diagram of a ring oscillator  350  implementing a capacitance measurement circuit  205  with capacitive-based sensor  202 . In some embodiments, capacitance measurement circuit  205  with capacitive-based sensor  202  may be carried out via ring oscillator  350 . In some embodiments, ring oscillator circuit  350  may measure values of capacitive-based sensor  202 , transferring such values of capacitive-based sensor  202  into frequency of oscillations of said ring oscillator  350 . 
         [0345]    Continuing discussing  FIG. 3 , in some embodiments, ring oscillator  350  may comprise an odd number of stages. In some embodiments, each such stage may comprise a respective digital invertor  310  and load capacitor  300 . In some embodiments, digital invertor  310  may be C-MOS pair  310 , which for example may be a combination of p-type and n-type field-effect transistors depicted in  FIG. 5B . In some embodiments, ring oscillator  350  may also comprise capacitive-based sensor  340  (located in some embodiments, after a last stage). In some embodiments, an oscillation frequency of ring oscillator circuit  350  man be found using expression (1): 
         [0000]    
       
         
           
             
               
                 
                   F 
                   = 
                   
                     1 
                     
                       2 
                        
                       N 
                        
                       
                           
                       
                        
                       τ 
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where N may be a number of stages and τ may be a delay of each stage, and where τ can be expressed as: 
         [0000]    
       
         
           
             
               
                 
                   τ 
                   = 
                   
                     
                       CV 
                       T 
                     
                     
                       I 
                       t 
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where C is a capacitance of each stage, V T  is a threshold voltage of a C-MOS pair  310 , and I t  is an average charging current of the load capacitor C of each stage. If the capacitance of the capacitive-based sensor  340  changes, the oscillation frequency of ring oscillator circuit  350  may change as well, according to the expressions above. 
         [0346]      FIG. 4A  through and including  FIG. 4E  may depict various capacitors, which may be used as capacitors in at least some of the circuit diagrams shown in the figures.  FIG. 4A  through and including  FIG. 4E  may depict various capacitors, which may be used as components in capacitive-based sensors  202 . 
         [0347]      FIG. 4A  may be a perspective view of a basic capacitor. In some embodiments, this basic capacitor may comprise two substantially parallel plates  400  that may be separated by dielectric material  401 . In some embodiments, such plates  400  may be separated from each by a distance of d. In some embodiments, plates  400  may be constructed from substantially conductive materials. In some embodiments, the capacitance of this basic capacitor may be found from the following expression (3): 
         [0000]    
       
         
           
             
               
                 
                   C 
                   = 
                   
                     
                       
                         ɛ 
                         0 
                       
                        
                       
                         ɛ 
                         r 
                       
                        
                       A 
                     
                     d 
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where A is an area of each of the conductive plates  400 , d is a width of the dielectric material  401  between the conductive plates  400 , ∈ r  is the relative permittivity of the dielectric material  401 , and ∈ 0 ≈8.85·10 −12  F/m is vacuum permittivity constant. 
         [0348]      FIG. 4B  may be a perspective view of a capacitor with substantially parallel regions of a conductive surface of type “A”  402  mounted to substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, the capacitor of  FIG. 4B  may comprise two pairs of substantially parallel regions of conductive surface of type “A”  402  mounted to substrate  403 . In some embodiments, conductive surface of type “A”  402  may be constructed from electrically conductive materials of construction. 
         [0349]      FIG. 4C  may be a top view of a capacitor; with substantially parallel regions of a conductive surface of type “B”  404 ; and with substantially parallel regions of a conductive surface of type “C”  405 . In some embodiments, conductive surface of type “B”  404  and conductive surface of type “C”  405  may be mounted to a same substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “B”  404  and conductive surface of type “C”  405  may be constructed from electrically conductive materials of construction. In some embodiments, conductive surface of type “C”  405  may be arranged in a pair of substantially parallel rows in a spiral fashion with substrate  403  disposed between or/and under such substantially parallel rows; for example, and without limiting the scope of the present invention, arranged as conductive wires in concentric circles on a dielectric substrate. 
         [0350]      FIG. 4D  may be a top view of a capacitor; with regions of a conductive surface of type “D”  406 ; and with regions of a conductive surface of type “E”  407 . In some embodiments, conductive surface of type “D”  406  and conductive surface of type “E”  407  may be mounted to a same substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “D”  406  and conductive surface of type “E”  407  may be constructed from electrically conductive materials of construction. In some embodiments, conductive surface of type “D”  406  may be arranged in concentric circles (in a bull&#39;s eye fashion) with substrate  403  disposed between such concentric circles. In some embodiments, conductive surface of type “E”  407  may be arranged in concentric squares with substrate  403  disposed between or/and under such concentric squares. 
         [0351]      FIG. 4E  may be a top view of a capacitor, with regions of a conductive surface of type “F”  408 . In some embodiments, the capacitor of  FIG. 4E  may have regions of conductive surface of type “F”  408  mounted to substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “F”  408  may be constructed from electrically conductive materials of construction. 
         [0352]      FIG. 4B ,  FIG. 4C ,  FIG. 4D , and  FIG. 4E  may depict examples of various capacitors that may be used in some capacitive-based sensors  202  embodiments. Such capacitors may form at least part of capacitive-based sensors  202  that may be the at least one sensor of a given monitoring-sensor-tag  120 . In some embodiments, capacitive-based sensors  202  may comprise one or more of: plates  400 , conductive surface type “A”  402 , conductive surface type “B”  404 , conductive surface type “C”  405 , conductive surface type “D”  406 , conductive surface type “E”  407 , and/or conductive surface type “F”  408 ; placed (e.g., mounted, installed, immersed, implanted, and/or the like) on a dielectric substrate  403  (and/or onto dielectric material  401  in some embodiments). 
         [0353]    Continuing discussing  FIG. 4B ,  FIG. 4C ,  FIG. 4D , and  FIG. 4E , in some embodiments, the given material-of-interest that may be the object of analysis, monitoring, and/or tracking may be the dielectric substrate  403 . Thus in use, material-of-interest, acting as dielectric substrate  403 , may substantially fill in and/or substantially cover one or more of: plates  400 , conductive surface type “A”  402 , conductive surface type “B”  404 , conductive surface type “C”  405 , conductive surface type “D”  406 , conductive surface type “E”  407 , and/or conductive surface type “F”  408 . Use of such capacitors in capacitive-based sensor  202  may permit monitoring and/or detection of structural defects in the material-of-interest (such as, but not limited to, cracks or changes in structure of material-of-interest). Because changes in structure of the material-of-interest acting as the dielectric substrate  403  may change the relative permittivity ∈ r  which, in turn, may change the capacitance of capacitive-based sensor  202  in communication with capacitance measurement circuit  205 . 
         [0354]    For example, and without limiting the scope of the present invention, a change in the relative permittivity ∈ r  of material-of-interest due to a structural change may be detected (registered) by capacitive-based sensor  340  in ring oscillator  350 , which may be one possible implementation of capacitance measurement circuit  205  with capacitive-based sensor  202 . That is, this change may register as a change in the frequency of ring oscillator  350 . Such frequency changes may be measured, monitored, tracked, and/or analyzed to provide strong indications of structural defects and/or of structural changes in the given material-of-interest. For example, and without limiting the scope of the present invention, the relative permittivity of concrete is approximately 4.5 times higher than the relative permittivity of air. Accordingly, any appearance of a crack in the concrete, that may permit air ingress, may then alter the capacitance of the implanted monitoring-sensor-tag  120  into the given material-of-interest, which in this example may be a section of concrete. A same concept may be applied to liquid ingress into structural defects and/or structural changes of other materials-of-interest, such as, but not limited to, dental-filling  1001 . 
         [0355]    Capacitive-based, resistance-based, inductance-based or other types of sensors as part of a given monitoring-sensor-tag  120 , that may be implanted to (i.e., attached to) the given material-of-interest, may also be used to measure temperature of the analyzed given material-of-interest, according to various embodiments of the present invention. 
         [0356]      FIG. 5A  may be a circuit diagram of a ring oscillator  500  implementing a capacitance measurement circuit  205  with capacitive-based sensor  202 . In some embodiments, capacitance measurement circuit  205  with capacitive-based sensor  202  may be carried out via ring oscillator  500 . In some embodiments, ring oscillator circuit  500  may measure values of capacitive-based sensor  202 , transferring such values of capacitive-based sensor  202  into frequency of oscillations of said ring oscillator  500 . In some embodiments, ring oscillator  500  may be used to monitor, track, and/or analyze temperature changes to the given material-of-interest where ring oscillator  500  may be implanted to (i.e., attached to). 
         [0357]    Continuing discussing  FIG. 5A , in some embodiments, ring oscillator  500  may comprises an odd number of stages. In some embodiments, each such stage may comprise a respective digital invertor  310  and load capacitor  300 . In some embodiments, digital invertor  310  may be C-MOS pair  310 . In some embodiments, ring oscillator  500  may also comprise capacitive-based sensor  340  (located in some embodiments, after a last stage) and a switch  501  in series with capacitive-based sensor  340 . 
         [0358]      FIG. 5B  may be a circuit diagram of C-MOS pair  310  (digital invertor  310 ). In some embodiments, C-MOS pair  310  (digital invertor  310 ) may comprise P-MOS transistor  502  and N-MOS transistor  503 . 
         [0359]    Continuing discussing  FIG. 5A  and  FIG. 5B , in some embodiments, ring oscillator  500  may comprise switch  501 . In some embodiments, switch  501  may connect or disconnect capacitive-based sensor  340  from ring oscillator  500 . Accordingly, the oscillation frequency of ring oscillator  500  may depend on an ambient temperature of the surrounding material-of-interest. Current I flowing through P-MOS transistor  502  and N-MOS transistor  503 , forming digital invertor  310 , may affect a delay of each stage, depending on the ambient temperature of the surrounding material-of-interest. In this manner, the ring oscillator  500 , with the switchable capacitive-based sensor  340 , may function as a temperature sensor for the monitored given material-of-interest. With switch  501  in a disconnected state, capacitive-based sensor  340  may not influence the oscillation frequency of ring oscillator  500 ; therefore the oscillation frequency of ring oscillator  500  may correlate with the ambient temperature of the surrounding material-of-interest. 
         [0360]    It should be appreciated by those of ordinary skill in the relevant art that resistance-based sensors  203  and resistance measurement circuits  206  may be used to implement configurations depicted in  FIG. 2B ,  FIG. 2D ,  FIG. 2F , and/or  FIG. 2G  to quantify, measure, track, monitor, and/or analyze various states and changes in states of materials-of-interest with one or more monitoring-sensor-tag  120  processing the one or more reading originating from such resistance-based sensors  203 . 
         [0361]      FIG. 6  may be a circuit diagram of a ring oscillator  600  implementing a resistance measurement circuit  206  with resistance-based sensor  203 . In some embodiments, ring oscillator  600  may be used to sense, measure, monitor, track, and/or analyze strains, force, torsion, and/or pressure in portions of material-of-interest with monitoring-sensor-tag  120 ; wherein the at least one sensor (of monitoring-sensor-tag  120 ) may comprise ring oscillator  600 . In the embodiment implemented and depicted in  FIG. 6 , ring oscillator  600  (e.g., implemented as resistance measurement circuit  206  with resistance-based sensor  203 ) may comprise resistance-based sensor  203 , an example of a strain-influenced resistor  602 ; wherein monitoring-sensor-tag  120  may comprise ring oscillator  600  and the at least one sensor (of monitoring-sensor-tag  120 ) may comprise a strain-influenced resistor  602 . Thus, ring oscillator  600  may be used to sense, measure, monitor, track, and/or analyze deformations, structural defects, and/or structural changes in material-of-interest. 
         [0362]    Continuing discussing  FIG. 6 , in some embodiments, ring oscillator circuit  600  may comprise an odd number of stages. In some embodiments, each such stage may comprise digital invertor  310  and an “RC pair.” In some embodiments, each such RC pair (except a final stage) may comprise a load capacitor  300  and a load resistor  601 . In some embodiments, a final stage RC pair may comprise a load capacitor  300  and a strain-influenced resistor  602 . In some embodiments, an oscillation frequency F of ring oscillator  600  may be determined from the expression (4): 
         [0000]    
       
         
           
             
               
                 
                   F 
                   = 
                   
                     
                       1 
                       
                         2 
                          
                         N 
                          
                         
                             
                         
                          
                         τ 
                       
                     
                     = 
                     
                       1 
                       
                         2 
                          
                         
                           N 
                           · 
                           
                             f 
                              
                             
                               ( 
                               
                                 RC 
                                 , 
                                 
                                   V 
                                   t 
                                 
                               
                               ) 
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where N may be a number of stages, τ may be a delay of each stage, f (RC,V t ) may be a function of the RC value of each stage, and of the threshold voltage of CMOS invertor (digital inventor  310 ) V t . In some embodiments, strain-influenced resistor  602  (denoted as R S  in  FIG. 6 ) may be a strain-influenced resistor. In some embodiments, ring oscillator  600  may be a component of the least one sensor of monitoring-sensor-tag  120  that may be attached to (i.e., implanted, immersed, and/or the like) to the given material-of-interest. And changes (e.g., strains, forces, torsion, pressure, structural changes, deformations, and/or the like) in the given material-of-interest may then translate into changes in the oscillation frequency F that ring oscillator  600  may be sensing, measuring, monitoring, tracking, and/or analyzing. 
         [0363]      FIG. 7A  may be a top view of an example of a stress sensor used in some embodiments of the present invention. In some embodiments, such a stress sensor may be the at least one sensor of monitoring-sensor-tag  120 . In some embodiments, the stress sensor depicted in  FIG. 7A  may be strain-influenced resistor  700 . In some embodiments, strain-influenced resistor  700  may be a part of an implementation of ring oscillator  600 , strain-influenced resistor  602 ; thus strain-influenced resistor  700  may be a type of resistance-based sensor  203  used to sense, measure, monitor, track, and/or analyze changes (e.g., strains, forces, torsion, pressure, structural changes, deformations, and/or the like) in the given material-of-interest by such changes to the material-of-interest may translate into changes in the oscillation frequency F that ring oscillator  600  may be sensing, measuring, monitoring, tracking, and/or analyzing. 
         [0364]      FIG. 7B  may be a top view of an example of a stress sensor used in some embodiments of the present invention. In some embodiments, such a stress sensor may be the at least one sensor of monitoring-sensor-tag  120 . In some embodiments, this stress sensor depicted in  FIG. 7B  may be an example of a resistance-based sensor  203 . In some embodiments, this stress sensor depicted in  FIG. 7B  may comprise thin-film-coating  701  and substrate  702 . In some embodiments, thin-film-coating  701  may be an electrically resistive compound. When monitoring-sensor-tag  120  with the stress sensor shown in  FIG. 7B  may be attached to (e.g., implanted, immersed, touching, and/or the like) the given material-of-interest, changes (e.g., strains, forces, torsion, pressure, structural changes, deformations, and/or the like) in the given material-of-interest may translate into changes in the resistance of thin-film-coating  701  which may be registered, sensed, measured, monitored, tracked, and/or analyzed by resistance-based sensor  203 . In some embodiments, substrate  702  may be a flexible non-conductive material upon which the thin-film-coating  701  may be attached or set upon. Physical forces acting on and causing various changes such as, but not limited to, possible fracturing, cracking, bending, twisting, excessive pressure, abnormal temperature, and/or the like, of substrate  702  may also change monitorable conductive qualities of thin-film coating  701 . 
         [0365]      FIG. 7C  may be a top view of an example of a stress sensor used in some embodiments of the present invention. In some embodiments, such a stress sensor may be the at least one sensor of monitoring-sensor-tag  120 . In some embodiments, this stress sensor depicted in  FIG. 7B  may be an example of a resistance-based sensor  203 . In some embodiments, the stress sensor depicted in  FIG. 7C  may be spiral-formed-electric-conductor  703 . In some embodiments, spiral-formed-electric-conductor  703  may be a type of resistance-based sensor  203 . In some embodiments, spiral-formed-electric-conductor  703  may be substantially spiral shaped. When monitoring-sensor-tag  120  with the stress sensor (e.g., spiral-formed-electric-conductor  703 ) shown in  FIG. 7C  may be attached to (e.g., implanted, immersed, touching, and/or the like) the given material-of-interest, changes (e.g., strains, forces, torsion, pressure, structural changes, deformations, and/or the like) in the given material-of-interest may translate into changes in the resistance of spiral-formed-electric-conductor  703  which may be registered, sensed, measured, monitored, tracked, and/or analyzed by resistance-based sensor  203 . 
         [0366]      FIG. 8  may be a diagrammatical top view of a monitoring-sensor-tag&#39;s  120  structure and components, as used in some embodiments of the present invention. In some embodiments, a given monitoring-sensor-tag  120  may be divided functionally and/or structurally into sensor-portion  801  and processing-portion  802 . While sensor-portion  801  and processing-portion  802  may be shown as distinct portions in  FIG. 8 , in some embodiments, sensor-portion  801  and processing-portion  802  may overlap. In some embodiments, sensor-portion  801  may comprise the at least one sensor. In some embodiments, processing-portion  802  may comprise at least one antenna  130  and at least one electric circuit  140 ; wherein at least one electric circuit  140  and at least one antenna  130  may be in communication with each other. In some embodiments, at least one electric circuit  140  may be in communication with sensor-portion  801 . 
         [0367]    In some embodiments, at least one electric circuit  140  may be in communication with sensor-portion with the at least one sensor. In some embodiments, at least one electric circuit  140  may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  may comprise processing circuitry  204  and may further comprise one or more of capacitive measurement circuit  205 , resistance measurement circuit  206 , and/or inductance measurement circuit  209 . 
         [0368]    Continuing discussing  FIG. 8 , as shown in  FIG. 8  the at least one sensor of sensor-portion  801  may comprise three distinct sensors: conductive surface type “B”  404 , conductive surface type “C”  405 , and strain-influenced resistor  700  (which may be a part [component] of an implementation of ring oscillator  600 ). See e.g.,  FIG. 4C ,  FIG. 6 , and  FIG. 7A ; as well as their respective discussions above. Continuing discussing  FIG. 8 , in some embodiments, strain-influenced resistor  700  may be strain influenced sensor. In some embodiments, conductive surface type “B”  404  and conductive surface type “C”  405  may function as compound integrity sensors that may allow for structural integrity analysis of the given material-of-interest where the given sensor may be implanted. In some embodiments, these three distinct sensors may be in communication with at least one electric circuit  140 . In some embodiments, at least one electric circuit  140  may provide control logic for controlling these three distinct sensors. In some embodiments, at least one electric circuit  140  may provide control logic for controlling these three distinct sensors by taking one or more readings from these three distinct sensors and instructing at least one antenna  130  in the transmission of such one or more readings for pickup by one or more readers  100 . 
         [0369]    Continuing discussing  FIG. 8 , while three distinct sensors may be shown in  FIG. 8 , it is expressly contemplated the at least one sensor of sensor-portion  801  may comprise one or more of the sensors discussed and shown in the accompanying figures. 
         [0370]    Continuing discussing  FIG. 8 , in some embodiments, sensor-portion  801  and processing-portion  802  may be manufactured as single and distinct articles of manufacture, that once assembled may be in communication with each other. In some embodiments, sensor-portion  801  and processing-portion  802  may be manufactured by printing as single and distinct articles of manufacture, that once assembled may be in communication with each other. 
         [0371]    Continuing discussing  FIG. 8 , in some embodiments, sensor-portion  801  and processing-portion  802  may be manufactured as a single integrated article of manufacture. In some embodiments, sensor-portion  801  and processing-portion  802  may be printed as a single integrated article of manufacture. 
         [0372]    As noted above, in some embodiments, upon at least one antenna  130  receiving electromagnetic (EM) radiation of a predetermined characteristic as an input from at least one antenna  110  of reader  100 , this input may cause at least one electric circuit  140  to take one or more readings from the at least one sensor and to then transmit such one or more readings using at least one antenna  130 .  FIG. 9  may be a diagram of control and status signals, in accordance with some embodiments of the present invention. In some embodiments, electric circuit  140  (or processing circuitry  204  in some embodiments) may be executing the functions shown in  FIG. 9 . 
         [0373]    Continuing discussing  FIG. 9 , in some embodiments, electric circuit  140  and/or processing circuitry  204  may be event-driven (or input-driven) and digital CLOCK  930  may implement events which condition time and orchestrate the functionality of electric circuit  140  and/or processing circuitry  204 . In some embodiments, CLOCK  930  may be digital clock. In some embodiments, CLOCK  930  may be a binary clock. In some embodiments, RESTART_COUNT signal  931  may change to binary value 1 for at least one CLOCK  930  cycle by electric circuit  140  (or processing circuitry  204  in some embodiments) receiving respective instruction(s) from reader  100 , as indicated at Pulse of RESTART_COUNT signal  938 . That is, Pulse of RESTART_COUNT signal  938  may be a response to at least one antenna  130  receiving electromagnetic (EM) radiation of a predetermined characteristic as an input from at least one antenna  110  of reader  100 , where this input may then cause at least one electric circuit  140  to take the one or more readings from the at least one sensor. In some embodiments, a RESTART_COUNT signal  931  may trigger resetting of a COUNTER  932 . In some embodiments, COUNTER  932  may store values from the at least one sensor; such as, the one or more readings. In some embodiments, COUNTER  932  may store values of a number of ring oscillator (e.g., ring oscillator  350  or ring oscillator  600 ) oscillations. In some embodiments, COUNTER  932  may be a digital register. In some embodiments, COUNTER  932  may be a binary counter. In some embodiments, COUNTER  932  may represent a state of a digital ripple counter, input of which may be connected to the last stage of ring oscillator (e.g., ring oscillator  350  or ring oscillator  600 ). In some embodiments, COUNTER  932  may have its value set to a zero value, as indicated at zero value  934 ; which may be triggered by Pulse of RESTART_COUNT signal  938  that may in turn trigger RESTART_COUNT signal  931 , which may in turn result in zero value  934  for COUNTER  932 . In some embodiments, if COUNTER  932  may reach a maximal value  937 , then a COUNTER_OVERFLOW signal  933  may be triggered; wherein this COUNTER_OVERFLOW signal  933  changes its binary value from 0 to 1, as indicated at “0-to-1 transition of Pulse of Counter Overflow signal  935 .” In that case, COUNTER_OVERFLOW signal  933  may stay at binary value 1 until a next change of RESTART_COUNT signal  931  from binary value 0 to 1 for at least one CLOCK  930  cycle, as indicated at “1-to-0 transition of Pulse of Counter Overflow signal  936 .” 
         [0374]    Optionally, in some embodiments, a value Y, stored in a divider register, may advance COUNTER  932  to the next value every Y CLOCK  930  cycles. That may prevent COUNTER  932  reaching its maximal value  937  too soon. 
         [0375]      FIG. 10A  may be a diagram of a patient  1328  tooth  1000  with one or more monitoring-sensor-tags  120  placed in a dental-filling  1001  as a material-of-interest, in accordance with some embodiments of the present invention.  FIG. 10A  may depict a schematic diagram of tooth  1000 . Tooth  1000  may comprise one or more dental-fillings  1001 .  FIG. 10A  may also depict gum  1002 , so as to schematically indicate a gum  1002  line in relation to tooth  1000  (for demonstration purposes). 
         [0376]    In  FIG. 10A , dental-filling(s)  1001  may be the material-of-interest. For example, and without limiting the scope of the present invention, dental-fillings  1001  may be selected from filling materials used in the practice of dentistry, such as, but not limited to “fill” cavities and/or to “seal” undesirable surface geometry on teeth  1000 . For example, and without limiting the scope of the present invention, dental-fillings  1001  may be selected from one or more of: composite resins; glass ionomer cements; resin-ionomer cements; porcelain (and/or ceramics); porcelain fused to a metal; and/or the like. 
         [0377]    Continuing discussing  FIG. 10A , in some embodiments, one or more monitoring-sensor-tags  120  may be attached to, located on, located in, immersed, implanted, and/or the like in the one or more dental-fillings  1001  of tooth  1000 . Note, characteristics (e.g., one or more readings) of such one or more monitoring-sensor-tags  120  placement with respect to one or more dental-fillings  1001  may change over time as the given one or more dental-fillings  1001  may cure and/or harden. In some embodiments, placement of one or more monitoring-sensor-tags  120  with respect to one or more dental-fillings  1001  may be random. In some embodiments, placement of one or more monitoring-sensor-tags  120  with respect to one or more dental-fillings  1001  may be substantially uniform. In some embodiments, placement of one or more monitoring-sensor-tags  120  with respect to one or more dental-fillings  1001  may be approximately uniform. In some embodiments, placement of one given monitoring-sensor-tags  120  (e.g., a first-sensor-tag  1020 ) with respect to another different monitoring-sensor-tags  120  (e.g., a second-sensor-tag  1021 ) may be specified (e.g., at a fixed distance such as at an initial predetermined spacing  1025 ) within the given material-of-interest, such as dental-filling  1001  (see e.g.,  FIG. 10D  discussed below). Thus, placement of such one or more monitoring-sensor-tag  120  with respect to one or more dental-fillings  1001  may be used to obtain various information about one or more dental-fillings  1001  and may do so in a non-invasive manner and in a manner that does not require use of ionizing imaging radiation. 
         [0378]      FIG. 10B  may be a diagram of a patient  1328  tooth  1000  with one or more monitoring-sensor-tags  120  placed in: a root-canal-cavity  1003 , in a root-canal-post  1004 , and/or in a dental-crown  1005 ; in accordance with some embodiments of the present invention. In  FIG. 10B  the material-of-interest may be selected from one or more of: root-canal-cavity  1003 , root-canal-post  1004 , dental-crown  1005 , and/or the like. In some embodiments, one or more monitoring-sensor-tags  120  may be attached to, located on, located in, immersed, implanted, and/or the like in the root-canal-cavity  1003 , the root-canal-post  1004 , and/or the dental-crown  1005 . In some embodiments, one or more monitoring-sensor-tags  120  may further comprise a standalone-strain-sensor  1006 . In some embodiments, standalone-strain-sensor  1006  may be an external sensor structure attached to a given monitoring-sensor-tag  120 . In some embodiments, standalone-strain-sensor  1006  may be a strain-influenced resistor  700  or a spiral-formed-electric-conductor  703 . In some embodiments, standalone-strain-sensor  1006  may be capacitive-based sensor  202  or a resistance-based sensor  203 . In some embodiments, standalone-strain-sensor  1006  may be in communication with one or more of: electric circuit  140 , processing circuitry  204 , capacitance measurement circuit  205 , and/or resistance measurement circuit  206 . 
         [0379]      FIG. 10C  may be a diagram of a patient  1328  tooth dental-implant  1007  with one or more monitoring-sensor-tags  120 , in accordance with some embodiments of the present invention. In some embodiments, dental-implant  1007 , which may be an artificial tooth, may comprise implant-post  1008 ; wherein implant-post  1008  may be anchored to patient  1328 . In  FIG. 10C , the material-of-interest may be dental-implant  1007  and/or implant-post  1008 . In some embodiments, one or more monitoring-sensor-tags  120  may be attached to, located on, located in, immersed, implanted, and/or the like in the dental-implant  1007  and/or in the implant-post  1008 . In some embodiments, one or more monitoring-sensor-tags  120  may further comprise a standalone-strain-sensor  1006 . In some embodiments, standalone-strain-sensor  1006  may be an external sensor structure attached to a given monitoring-sensor-tag  120 . In some embodiments, standalone-strain-sensor  1006  may be a strain-influenced resistor  700  or a spiral-formed-electric-conductor  703 . In some embodiments, standalone-strain-sensor  1006  may be capacitive-based sensor  202  or a resistance-based sensor  203 . In some embodiments, standalone-strain-sensor  1006  may be in communication with one or more of: electric circuit  140 , processing circuitry  204 , capacitance measurement circuit  205 , and/or resistance measurement circuit  206 . 
         [0380]      FIG. 10D  may be a diagram of a first-sensor-tag  1020  and a second-sensor-tag  1021  arranged in a material-of-interest with an initial predetermined spacing  1025  between the first-sensor-tag  1020  and the second-sensor-tag  1021  in the material-of-interest  1028 . Note, in some embodiments, material-of-interest  1028  shown in  FIG. 10D  may be any material-of-interest noted herein. For example, and without limiting the scope of the present invention, in some embodiments, material-of-interest  1028  may be selected from one or more of: dental-filling  1001 , root-canal-cavity  1003 , root-canal-post  1004 , dental-crown  1005 , dental-implant  1007 , implant-post  1008 , an article implantable within a body of an organism (e.g., where the organism is patient  1328 ), the article attachable to the body of the organism, specific tissue of the organism, and/or a construction member. 
         [0381]    Continuing discussing  FIG. 10D , in some embodiments, each of first-sensor-tag  1020  and/or of second-sensor-tag  1021  may comprise a lattice-of-sensors  1023  (e.g.,  202 ,  203 ,  406 ,  407 ,  700 ,  703 , and/or  1006 ); wherein each respective lattice-of-sensors  1023  may be separated from each other lattice-of-sensors  1023  by initial predetermined spacing  1025 . And in some embodiments, sensors within a given lattice (e.g., lattice-of-sensors  1023 ) may be separated by sensor-spacing  1026 . Because initial predetermined spacing  1025  may be known, then positional locations of the other one or more monitoring-sensor-tags  120  may be determined. Likewise, because initial predetermined spacing  1026  may be known, then positional locations of the sensors within a given lattice (e.g., lattice-of-sensors  1023 ) may be determined. In some embodiments, each lattice-of-sensors  1023  (e.g., of each first-sensor-tag  1020  and/or of second-sensor-tag  1021 ) may comprise a plurality of sensors (e.g.,  202 ,  203 ,  406 ,  407 ,  700 ,  703 , and/or  1006 ); wherein this plurality of sensors may be attached to the given sensor-tag, such as first-sensor-tag  1020  and/or second-sensor-tag  1021 . In some embodiments, each such sensor-tag (e.g., first-sensor-tag  1020  and/or second-sensor-tag  1021 ) may comprise their own electric circuit  140  (or processing circuitry  204 ). In some embodiments, the plurality of sensors (e.g.,  202 ,  203 ,  406 ,  407 ,  700 ,  703 , and/or  1006 ) of each lattice-of-sensors  1023  may be in communication with such an electric circuit  140  (or processing circuitry  204 ) but located outside of such an electric circuit  140 . See e.g.,  FIG. 10D . In some embodiments, first-sensor-tag  1020  and second-sensor-tag  1021  may be types of monitoring-sensor-tags  120  with initial predetermined spacing  1025  known between them. Also in some embodiments, there may be a plurality of first-sensor-tag  1020  and a plurality of second-sensor-tag  1021 . 
         [0382]    In some embodiments, a given lattice-of-sensors  1023  may be arranged in a one dimensional, two dimensional, or three dimensional configuration. In some embodiments, a given lattice-of-sensors  1023  may be arranged in mesh configuration. In some embodiments, a given lattice-of-sensors  1023  may be arranged in lattice configuration. 
         [0383]    Note, initial predetermined spacing  1025  may change over time. For example, as the given material-of-interest  1028  may cure and/or harden, initial predetermined spacing  1025  may alter. In some embodiments, initial predetermined spacing  1025  may be calibrated before and after such curing and/or hardening of material-of-interest  1028 . 
         [0384]    Note,  FIG. 10D  may also depict a known coordinate system and known origin  1325  (i.e., origin  1325  of chosen coordinate system). Origin  1325  and a chosen coordinate system may be further discussed in the  FIG. 13A  discussion below. 
         [0385]      FIG. 11A  may be a diagrammatical top view (or a side view in some embodiments) of a reader-and-calibration-member  1109 , in accordance with some embodiments of the present invention. In some embodiments, reader-and-calibration-member  1109  may comprise one or more readers  100 . In some embodiments, reader-and-calibration-member  1109  may comprise one or more reference-sensor-tags  1102 . In some embodiments, reader-and-calibration-member  1109  may comprise a reader-housing-member  1108 . In some embodiments, reader-and-calibration-member  1109  may comprise a reference-housing-member  1107 . In some embodiments, reader-and-calibration-member  1109  may comprise one or more of: reader-housing-member  1108 , reader  100 , reference-housing-member  1107 , and reference-sensor-tags  1102 . In some embodiments, reader-and-calibration-member  1109  may house reader-housing-member  1108  and reference-housing-member  1107 . In some embodiments, reader-housing-member  1108  may house one or more readers  100 . In some embodiments, reference-housing-member  1107  may house one or more reference-sensor-tags  1102 . In some embodiments, reader-and-calibration-member  1109  may be a structural member. In some embodiments, reader-housing-member  1108  may be a structural member. In some embodiments, reference-housing-member  1107  may be a structural member. In some embodiments, reader-and-calibration-member  1109  may be rigid to semi-rigid. In some embodiments, reader-housing-member  1108  may be rigid to semi-rigid. In some embodiments, reference-housing-member  1107  may be rigid to semi-rigid. In some embodiments reader-housing-member  1108  may be separated from reference-housing-member  1107  by a member-separation-distance  1110 . In some embodiments, a given reader  100  may be separated from a given reference-sensor-tag  1102  by a reader-tag-separation-distance  1111 . In some embodiments, member-separation-distance  1110  and/or reader-tag-separation-distance  1111  may be known (predetermined) and fixed distances. In some embodiments, member-separation-distance  1110  and/or reader-tag-separation-distance  1111  may be changed to a number of different known distances. 
         [0386]    In some embodiments, a given reference-sensor-tag  1102  may be a wireless sensor tag. In some embodiments, a given reference-sensor-tag  1102  may be one or more of: a RFID (radio frequency identification) sensor tag; a NFC (near field communication) sensor tag; a backscatter sensor tag; and/or magnetic inductive activated sensor tag. 
         [0387]    Continuing discussing  FIG. 11A , in some embodiments, a given reference-sensor-tag  1102  may be structurally the same or substantially the same as a given monitoring-sensor-tag  120 , except that reference-sensor-tags  1102  are not attached to the given material-of-interest. Rather, in some embodiments, reference-sensor-tags  1102  may be attached to reader-and-calibration-member  1109 , reference-housing-member  1107 , and/or fixed with respect to a given set of at least one antennas  110  of readers  100 . Thus, for the structures of reference-sensor-tags  1102 , refer back to disclosed and discussed structures for monitoring-sensor-tags  120 . That is, in some embodiments, each reference-sensor-tag  1102  may comprise at least one second-electric-circuit (which may be structurally the same or substantially the same to electric circuit  140  or processing circuitry  204 ). In some embodiments, each reference-sensor-tag  1102  may comprise at least one second-sensor (which may be structurally the same or substantially the same to various sensors discussed and disclosed herein, such as, but not limited to capacitive-based sensor  202  and/or resistance-based sensor  203 ). In some embodiments, each reference-sensor-tag  1102  may comprise at least one fourth-antenna (which may be structurally the same or substantially the same to at least one antenna  130 ). In some embodiments, the at least one fourth-antenna may be in communication with the at least one second-electric-circuit. In some embodiments, the at least one second-electric-circuit may be in communication with the at least one second-sensor. In some embodiments, when at least one fourth-antenna may receive electromagnetic (EM) signaling (e.g., radio waves from at least one antenna  110  of a given reader  100 ), then the at least one second-electric-circuit may take (or cause to be taken) one or more “calibration-readings” from the at least one second-sensor and then the at least one second-electric-circuit may cause transmission of such one or more calibration-readings using the at least one fourth-antenna, back to the at least one antenna  110  of that given reader  100 . 
         [0388]    Note, in terms of terminology nomenclature, when the term “fourth-antenna” may be used (which may be an antenna of a reference-sensor-tags  1102 ), then antenna  130  may be a “first-antenna,” and antenna  110  may be a “second-antenna,” and a “third-antenna” may be an antenna of position-reference-tag  1203  to be discussed below in a  FIG. 12  discussion below. 
         [0389]    Continuing discussing  FIG. 11A , in some embodiments, each reader  100  (of reader-and-calibration-member  1109 ) may comprise at least one antenna  110 . In some embodiments, each reference-sensor-tag  1102  may be fixed to each at least one antenna  110  of reader  100 . In some embodiments, each reference-sensor-tag  1102  may be fixed to each at least one antenna  110  of reader  100  at predetermined distance(s). In some embodiments, a minimum of such predetermined distance may be substantially reader-tag-separation-distance  1111  or approximated by reader-tag-separation-distance  1111 . In some embodiments, each reference-sensor-tag  1102  may comprise the at least one fourth-antenna. In some embodiments, each at least one fourth-antenna may be fixed with respect to each at least one antenna  110  of each reader of each reader-and-calibration-member  1109 . 
         [0390]      FIG. 11B  may be a diagrammatical top view of a reader-and-calibration-member  1109 , in accordance with some embodiments of the present invention. Reader-and-calibration-member  1109  shown in  FIG. 11B , as compared against  FIG. 11A  discussed above, may depict additional detail, in that in  FIG. 11B  the at least one antennas  110  of each reader  100  of reader-and-calibration-member  1109  may be shown. In  FIG. 11B , reader-antenna-tag-separation-distance  1112  may be depicted. In some embodiments, reader-antenna-tag-separation-distance  1112  may be a predetermined and fixed distance between a given at least one antenna  110  and a given reference-sensor-tag  1102 . In some embodiments, reader-antenna-tag-separation-distance  1112  may be a predetermined and fixed distance between a given at least one antenna  110  and a given at least one fourth-antenna of a given reference-sensor-tag  1102 . In some embodiments, each at least one antenna  110  of each reader  100  (of reader-and-calibration-member  1109 ) may be fixed with respect to each reference-sensor-tags  1102 . In some embodiments, reader-antenna-tag-separation-distance  1112  may be changed to a number of different known distances. 
         [0391]      FIG. 11C  may be a diagrammatical top view of a reader-and-calibration-member  1109  with an antenna-interface  1115 , in accordance with some embodiments of the present invention. Reader-and-calibration-member  1109  shown in  FIG. 11C , as compared against  FIG. 11A  discussed above, may depict additional detail, in that in  FIG. 11C  the at least one antennas  110  of each reader  100  of reader-and-calibration-member  1109  may be shown. In  FIG. 11C , reader-antenna-tag-separation-distance  1113  may be depicted. In some embodiments, reader-antenna-tag-separation-distance  1113  may be a predetermined and fixed distance between a given at least one antenna  110  and a given reference-sensor-tag  1102 . In some embodiments, reader-antenna-tag-separation-distance  1113  may be a predetermined and fixed distance between a given at least one antenna  110  and a given at least one fourth-antenna of a given reference-sensor-tag  1102 . In some embodiments, each at least one antenna  110  of each reader  100  (of reader-and-calibration-member  1109 ) may be fixed with respect to each reference-sensor-tags  1102 . 
         [0392]    Reader-and-calibration-member  1109  shown in  FIG. 11C , as compared against  FIG. 11B  discussed above, may depict additional detail, in that in  FIG. 11C  antenna-interface  1115  may be shown. In some embodiments, a given reader  100  may comprise antenna-interface  1115  and at least one antenna  110 . In some embodiments, antenna-interface  1115  may be in communication with each at least one antenna  110  for that given reader  100 . In some embodiments, antenna-interface  1115  may be hardware block. In some embodiments, antenna-interface  1115  may facilitate communications between at least one antenna  110  and one or more of: a control circuit and/or a processor  1801  (or processing module) (see e.g.,  FIG. 18 ). Continuing discussing  FIG. 11C , in some embodiments, antenna-interface  1115  may function in communication routing and/or function as a duplex. In some embodiments, antenna-interface  1115  may translate data and/or commands from the control circuit and/or processor  1801  (or processing module) into signals for transmission via at least one antenna  110 . In some embodiments, antenna-interface  1115  may translate signals received via at least one antenna  110  into data (e.g., the one or more readings and/or the one or more calibration-readings) and/or commands destined for the control circuit and/or for processor  1801  (or processing module). 
         [0393]    With respect to  FIG. 11A ,  FIG. 11B , and/or  FIG. 11C , in a given reader-and-calibration-member  1109 , locations of all included reference-sensor-tags  1102  relative to all included readers  100  and all included at least one antennas  110 , may be known parameters, or may be mathematically determined, thus allowing a calibration process to increase precision of the one or more readings from monitoring-sensor-tag  120  attached to a given material-of-interest. 
         [0394]    Note in some embodiments, disclosed structures and functions for a given reader-and-calibration-member  1109  may apply to a given reader  100 . That is, in some embodiments, a given reader  100  may be the given reader-and-calibration-member  1109 . 
         [0395]      FIG. 12  may be a diagrammatical side view (or a top view or a bottom view, in some embodiments) of a position-reference-member  1204 , in accordance with the present invention. In some embodiments, position-reference-member  1204  may be a structural member. In some embodiments, position-reference-member  1204  may be rigid to semi-rigid. In some embodiments, during use, position-reference-member  1204  may be fixed with respect to patient  1328 . In some embodiments, position-reference-member  1204  may comprise one or more position-reference-tags  1203 . In some embodiments, position-reference-member  1204  may house one or more position-reference-tags  1203 . In some embodiments, one or more position-reference-tags  1203  located on position-reference-member  1204  may be arranged in known and/or predetermined positions (i.e., configurations and/or patterns). For example, and without limiting the scope of the present invention, as shown in  FIG. 12 , the position-reference-tags  1203  may be arranged in a substantially linear (straight) arrangement in (on) position-reference-member  1204 . The position-reference-tags  1203  may also be arranged in an arbitrary arrangement in (on) position-reference-member  1204 . 
         [0396]    In some embodiments, a given position-reference-tag  1203  may be a wireless sensor tag. In some embodiments, a given position-reference-tag  1203  may be one or more of: a RFID (radio frequency identification) sensor tag; a NFC (near field communication) sensor tag; a backscatter sensor tag; and/or a magnetic inductive activated sensor tag. 
         [0397]    Continuing discussing  FIG. 12 , in some embodiments, a given position-reference-tag  1203  may be structurally the same or substantially the same as a given monitoring-sensor-tag  120 , except that position-reference-tags  1203  are not attached to the given material-of-interest. And in some embodiments, position-reference-tags  1203  may not comprise a sensor. Rather, in some embodiments, position-reference-tags  1203  may be attached to position-reference-member  1204 . Thus for the structures of position-reference-tags  1203  refer back to disclosed and discussed structures for monitoring-sensor-tags  120 . That is, in some embodiments, each position-reference-tag  1203  may comprise their own electric-circuit (which may be structurally the same or substantially the same to electric circuit  140 , but without elements to handle processing from a sensor). In some embodiments, each position-reference-tag  1203  may comprise at least one third-antenna (which may be structurally the same or substantially the same to at least one antenna  130 ). In some embodiments, the at least one third-antenna may be in communication with its own electric-circuit. In some embodiments, when at least one third-antenna may receive electromagnetic (EM) signaling (e.g., radio waves from at least one antenna  110  of a given reader  100 ), then the electric-circuit of position-reference-tag  1203  may cause transmission of “calibration-signals” from the at least one third-antenna to be transmitted back to the at least one antenna  110  of that given reader  100 . 
         [0398]    Note, in terms of terminology nomenclature, when the term “fourth-antenna” may be used (which may be an antenna of a reference-sensor-tags  1102 ), then antenna  130  may be a “first-antenna,” and antenna  110  may be the “second-antenna,” and the “third-antenna” may be the antenna of position-reference-tag  1203 . 
         [0399]    Also note, any antenna disclosed herein, in some embodiments, may be selected from one or more of: monostatic, bistatic, or multistatic. Further note, any antenna disclosed herein, in some embodiments, may be selected from one or more of: only for receiving, only for transmitting, or for both receiving and transmitting. And further note, receiving and/or transmitting may comprise signals for communication purposes, but also signals for energy transmission, harvesting, and usage. 
         [0400]    Continuing discussing  FIG. 12 , in some embodiments, positions (locations) of position-reference-tags  1203  may be known with respect to a given origin (e.g., origin  1325  of  FIG. 13A  and  FIG. 13C ) and/or a given coordinate system (e.g., a three-dimensional coordinate system, a Cartesian coordinate system, a radial coordinate system, or other well-known coordinate system). Because positions (locations) of position-reference-tags  1203  may be known, positions (locations) of reader(s)  100  may be determined relative to the position-reference-tags  1203  associated with the position-reference-member  1204 . Because positions (locations) of position-reference-tags  1203  may be known, positions (locations) of antennas  110  of reader(s)  100  may be determined relative to the position-reference-tags  1203  associated with the position-reference-member  1204 . The positions (locations) of readers  100  (or their antennas  110 ) may then be specified relative to a chosen three-dimensional coordinate system. See e.g.,  FIG. 13A  and  FIG. 13C . 
         [0401]      FIG. 13A  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags  120  that may be in and/or on patient  1328 ; wherein the system comprises a translating-scan-member  1326  that may translate along a predetermined path of motion. 
         [0402]    In some embodiments,  FIG. 13A  may depict a three-dimensional Cartesian coordinate system chosen to determine three-dimensional coordinates of a plurality of position-reference-tags  1203  affixed to position-reference-member  1204 , relative to which the positions (locations) of readers  100  may then be determined. In some embodiments, three dimensional coordinates of at least some of the plurality of position-reference-tags  1203  may be specified relative to the chosen Cartesian coordinate system defined by known origin  1325 , Imaginary x-axis  1320 , Imaginary y-axis  1321 , and Imaginary z-axis  1322 . Positions (locations) of reference-sensor-tags  1102  affixed to reader-and-calibration-member  1109  and the positions of the monitoring-sensor-tag  120  may also be specified relative to the chosen coordinate system. 
         [0403]    Continuing discussing  FIG. 13A , in some embodiments, translating-scan-member  1326  may comprise reader-and-calibration-member  1109 . In some embodiments, reader-and-calibration-member  1109  may be attached to translating-scan-member  1326 . In some embodiments, reader-and-calibration-member  1109  may comprise one or more reference-sensor-tags  1102 . In some embodiments, reader-and-calibration-member  1109  may comprise one or more readers  100 . In some embodiments, reference-sensor-tags  1102 , readers  100 , and/or antenna-interface  1115  (where antenna-interface  1115  may be in electrical communication with the readers  100 ) may be in electrical communication with translating-scan-member  1326 . In some embodiments, translating-scan-member  1326  may be in electrical communication with a processor  1801 . 
         [0404]    Continuing discussing  FIG. 13A , in some embodiments, the one or more monitoring-sensor-tags  120  may be located on or in the given material-of-interest, which may be on or in patient  1328 . In some embodiments, the material-of-interest, may be on or in a head of patient  1328 . In some embodiments, the material-of-interest, may be on or in a mouth of patient  1328 . In some embodiments, the material-of-interest, may be on or in: tooth  1000 , dental-filling  1001 , gum  1002 , root-canal-cavity  1003 , root-canal-post  1004 , dental-crown  1005 , dental-implant  1007 , and/or implant-post  1008  of patient  1328 . Note in some embodiments, at least some of the one or more monitoring-sensor-tags  120  utilized in the system shown in  FIG. 13A  may comprise one or more standalone-strain-sensor  1006 . See e.g.,  FIG. 18  which may be applied to the system shown in  FIG. 13A . 
         [0405]    Continuing discussing  FIG. 13A , in some embodiments, the system may comprise patient-fixation-member  1327 . In some embodiments, patient-fixation-member  1327  may removably support at least a portion of patient  1328 . In some embodiments, patient-fixation-member  1327  may be a structural member. In some embodiments, patient-fixation-member  1327  may be substantially rigid to semi-rigid, not including any portions with padding. In some embodiments, patient-fixation-member  1327  may be supported structurally by support  1329 . In some embodiments, support  1329  may attach to patient-fixation-member  1327 . In some embodiments, support  1329  may be a structural member. In some embodiments, support  1329  may be a rigid to semi-rigid. In some embodiments, patient-fixation-member  1327  may removably support the at least the portion of patient  1328  such that the supported portion of patient  1328  may be held relatively (sufficiently) fixed (with respect to origin  1325 ) during scanning, when translating-scan-member  1326  may be translating and travelling along the predetermined path of motion and the readers  100  (of reader-and-calibration-member  1109 ) may be scanning. In some embodiments, patient  1328  may breathe normally and blink normally, as a scanning frequency may be comparatively faster that such normal motions of patient  1328  may not adversely affect processing of received readings and transmissions from monitoring-sensor-tag  120  and/or from position-reference-tags  1203 . In some embodiments, patient-fixation-member  1327  may comprise a chin rest to removably support a chin of patient  1328 . In some embodiments, patient-fixation-member  1327  may comprise position-reference-member  1204 ; and position-reference-member  1204  may comprise one or more position-reference-tags  1203 . In some embodiments, position-reference-member  1204  may be attached to patient-fixation-member  1327 . In some embodiments, position-reference-member  1204  may be attached to patient-fixation-member  1327  at the chin rest. During scanning, position-reference-member  1204  may be fixed with respect to origin  1325  and the chosen coordinate system. During scanning, the one or more position-reference-tags  1203  of position-reference-member  1204  may be fixed with respect to origin  1325  and the chosen coordinate system. Recall, in some embodiments, position-reference-member  1204  may house the one or more position-reference-tags  1203 . 
         [0406]    Continuing discussing  FIG. 13A , in some embodiments, the predetermined path of motion of translating-scan-member  1326  may translate substantially around patient-fixation-member  1327 , which may be removably supporting the at least the portion of patient  1328 . In some embodiments, this predetermined path of motion may be curved, sinuous, arcing, ellipsoidal, circular, semi-circular, and/or the like. In some embodiments, translating-scan-member  1326  may be a rotating-scan-member. 
         [0407]      FIG. 13B  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags  120  that may be in and/or on patient  1328 ; wherein the system comprise a reader-housing-member  1108  with one or more readers  100  that may communicate with the one or monitoring-sensor-tags  120 . The system shown in  FIG. 13B  may differ fundamentally from the system shown in  FIG. 13A , by the system in  FIG. 13B  not utilizing a translating-scan-member  1326 ; that is, scanning in the system in  FIG. 13B , may be accomplished without translation mechanics; that is, the scanning in the system of  FIG. 13B  may be accomplished statically (fixedly). 
         [0408]    Continuing discussing  FIG. 13B , in some embodiments, the one or more monitoring-sensor-tags  120  may be located on or in the given material-of-interest, which may be on or in patient  1328 . In some embodiments, the material-of-interest, may be on or in a head of patient  1328 . In some embodiments, the material-of-interest, may be on or in a mouth of patient  1328 . In some embodiments, the material-of-interest, may be on or in: tooth  1000 , dental-filling  1001 , gum  1002 , root-canal-cavity  1003 , root-canal-post  1004 , dental-crown  1005 , dental-implant  1007 , and/or implant-post  1008  of patient  1328 . Note in some embodiments, at least some of the one or more monitoring-sensor-tags  120  utilized in the system shown in  FIG. 13B  may comprise one or more standalone-strain-sensor  1006 . See e.g.,  FIG. 18  which may be applied to the system shown in  FIG. 13B . 
         [0409]    Continuing discussing  FIG. 13B , in some embodiments, the system may comprise patient-fixation-member  1327 . In some embodiments, patient-fixation-member  1327  may removably supports at least a portion of patient  1328 . In some embodiments, patient-fixation-member  1327  may be a structural member. In some embodiments, patient-fixation-member  1327  may be substantially rigid to semi-rigid, not including any portions with padding. In some embodiments, patient-fixation-member  1327  may be supported structurally by support  1329  (not shown in  FIG. 13B ). In some embodiments, support  1329  may attach to patient-fixation-member  1327 . In some embodiments, support  1329  may be a structural member. In some embodiments, support  1329  may be a rigid to semi-rigid. In some embodiments, patient-fixation-member  1327  may removably supports the at least the portion of patient  1328  such that the supported portion of patient  1328  may be held relatively (sufficiently) fixed (with respect to origin  1325 ) during scanning, when readers  100  and/or reference-sensor-tags  1102  may be wirelessly transmitting and/or wirelessly receiving transmissions. In some embodiments, patient  1328  may breathe normally and blink normally, as a scanning frequency may be comparatively faster that such normal motions of patient  1328  may not adversely affect processing of received readings and transmissions from monitoring-sensor-tag  120  and/or from reference-sensor-tags  1102 . In some embodiments, patient-fixation-member  1327  may comprise a chin rest to removably support a chin of patient  1328 . In some embodiments, patient-fixation-member  1327  may comprise reader-housing-member  1108 ; and reader-housing-member  1108  may comprise one or more readers  100 . In some embodiments, reader-housing-member  1108  may be attached to patient-fixation-member  1327 . In some embodiments, reader-housing-member  1108  may be attached to patient-fixation-member  1327  at the chin rest (now shown in  FIG. 13B ). In some embodiments, reader-housing-member  1108  may be at least partially curved so as to arrange readers  100  at least partially around target regions to be scanned, i.e., the material(s)-of-interest with the one or more monitoring-sensor-tags  120  to be scanned. In some embodiments, arrangement of readers  100 , via geometry of reader-housing-member  1108  may also locate at least some readers  100  above and below the material(s)-of-interest with the one or more monitoring-sensor-tags  120  to be scanned. 
         [0410]    Continuing discussing  FIG. 13B , in some embodiments, patient-fixation-member  1327  may comprise reference-housing-member  1107 ; and reference-housing-member  1107  may comprise one or more reference-sensor-tags  1102 . In some embodiments, reference-housing-member  1107  may be attached to patient-fixation-member  1327 . In some embodiments, reference-housing-member  1107  may be attached to patient-fixation-member  1327  at the chin rest. In some embodiments, reference-housing-member  1107  may be at least partially curved so as to arrange reference-sensor-tags  1102  at least partially around target regions to be scanned, i.e., the material(s)-of-interest with the one or more monitoring-sensor-tags  120  to be scanned by readers  100 . In some embodiments, arrangement of reference-sensor-tags  1102 , via geometry of reference-housing-member  1107  may also locate at least some reference-sensor-tags  1102  above and/or below the material(s)-of-interest with the one or more monitoring-sensor-tags  120  to be scanned. In some embodiments, reference-housing-member  1107  may be substantially parallel with reader-housing-member  1108 . In some embodiments, reference-housing-member  1107  may be located below, above, or both below and above reader-housing-member  1108 . During scanning, readers  100  and/or reference-sensor-tags  1102  may be fixed with respect to patient-fixation-member  1327 . Recall, in some embodiments, positions (locations) of reference-sensor-tags  1102  may be known or mathematically determined (derived). 
         [0411]      FIG. 13C  may depict a system for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor-tags  120  that may be in and/or on patient  1328 ; wherein the system comprises a translating-scan-member  1326  that may translate along a predetermined path of motion. The system shown in  FIG. 13C  may be more akin to the system of  FIG. 13A , in that both systems may utilize a type of translating-scan-member  1326  but with different predetermined paths of motion. In some embodiments, translating-scan-member  1326  of  FIG. 13C  may be a reciprocating translating member, wherein the predetermined path may be substantially linear (straight). Also, the patient-fixation-member  1327  utilized in the system of  FIG. 13C  may also be structurally different from the patient-fixation-member  1327  shown in  FIG. 13A . In some embodiments, patient-fixation-member  1327  of  FIG. 13C  may be a platform for supporting up to all of patient  1328  upon such a platform. In some embodiments, patient  1328  may lay (in various positions) upon this platform embodiment of patient-fixation-member  1327 . In some embodiments, the predetermined path may have a length that substantially matches a length of this platform embodiment of patient-fixation-member  1327 . In some embodiments, the predetermined path may have a width that substantially matches a width of this platform embodiment of patient-fixation-member  1327 ; in which case, translating-scan-member  1326  may also translate in a side to side motion as well as reciprocating along the length of the predetermined path. Or in some embodiments, a width of reader-and-calibration-member  1109  may be sufficient wide to accommodate scanning the width of this platform embodiment of patient-fixation-member  1327 . 
         [0412]    Continuing discussing  FIG. 13C , the material(s)-of-interest with the one or more monitoring-sensor-tags  120  may be located on or in patient  1328 . In some embodiments, the material(s)-of-interest with the one or more monitoring-sensor-tag  120  may be located anywhere on or in patient  1328 . In some embodiments, the material(s)-of-interest with the one or more monitoring-sensor-tag  120  need not be constrained to a head region (nor to a mouth region) of patient  1328 . For example, and without limiting the scope of the present invention, as shown in  FIG. 13C , the material-of-interest with the one or more monitoring-sensor-tags  120  may be located in (or on) a left leg region of patient  1328 . Note in some embodiments, at least some of the one or more monitoring-sensor-tags  120  utilized in the system shown in  FIG. 13C  may comprise one or more standalone-strain-sensor  1006 . See e.g.,  FIG. 18  which may be applied to the system shown in  FIG. 13C . 
         [0413]      FIG. 14A  may be a schematic view of a single monitoring-sensor-tag  120  and a plurality of readers  100  that may communicate (wirelessly) with the single monitoring-sensor-tag  120 . Thus, the arrangement of  FIG. 14A  may be applicable to the system of  FIG. 13B . Knowing the positions (locations) of the readers  100 , then a position (location) of the single monitoring-sensor-tag  120  may be determined. Prior to such position (location) determination, the single monitoring-sensor-tag  120  may have unknown coordinates (e.g., x, y, and z in a Cartesian coordinate system). Whereas, in some embodiments, the readers  100  may have known (or determinable) coordinates relative to the chosen coordinate system, which may include a known origin. A process (method) for determining the coordinates of the single monitoring-sensor-tag  120  may be utilized to determine position (location) of all such monitoring-sensor-tags  120  in use in a given system. And thus, positions (locations) corresponding to the readings from sensors (e.g.,  202 ,  203 ,  1006 , and/or the like) of the given monitoring-sensor-tags  120  may be determined and analyzed, with respect to the given material-of-interest that is associated with the monitoring-sensor-tags  120 . 
         [0414]      FIG. 14B  may be a schematic view of a single monitoring-sensor-tag  120  and a single reader  100 ; wherein the single reader  100  may translate (in direction-of-motion  1400 ) with respect to the single monitoring-sensor-tag  120 ; and wherein the single reader  100  and the single monitoring-sensor-tag  120  may be in wireless communication. Thus, the arrangement of  FIG. 14B  may be applicable to the system of  FIG. 13A  (and/or the system of  FIG. 13C ). 
         [0415]    In some embodiments, knowing the positions (locations) of the single reader  100  as a function of time, a position (location) of the single monitoring-sensor-tag  120  (which may be fixed during scanning) may be determined. Prior to such position (location) determination, the single monitoring-sensor-tag  120  may have unknown coordinates (e.g., x, y, and z in a Cartesian coordinate system). Whereas, in some embodiments, the translating single reader  100  may have known (or determinable) coordinates relative to the chosen coordinate system and as a function of time, which may include a known origin or known starting position at a starting time. A process (method) for determining the coordinates of the single monitoring-sensor-tag  120  may be utilized to determine position (location) of all such monitoring-sensor-tags  120  in use in a given system. And thus, positions (locations) corresponding to the readings from sensors (e.g.,  202 ,  203 ,  1006 , and/or the like) of the given monitoring-sensor-tags  120  may be determined and analyzed, with respect to the given material-of-interest that is associated with the monitoring-sensor-tags  120 . 
         [0416]    Determining positions (locations) of any given monitoring-sensor-tag  120 , and/or determination of any given reader  100 , may involve well-known local position systems (LPS) techniques; that may utilize one or more of the following mathematical techniques: triangulation, trilateration, multilateration, combinations thereof, and/or the like. Additionally, such information may be utilized in such positional calculations: known reference points (e.g., origin  1325  and/or known locations of position-reference-tags  1203 ); direct paths (line of sight or LoS); angle of incidence (or angle of arrival or AoA); phase difference of arrival (PDoA); received signal strength indicator (RSSI); time of arrival (ToA); time of flight (ToF); and/or time difference of arrival (TDoA). 
         [0417]    For example, the following discussion presents one method for determining position (location) information of a given monitoring-sensor-tag  120  according to the configuration of  FIG. 14A . Let us stipulate that reader  100  number i has coordinates (x i , y i , z i ). The actual distance (range) between the given monitoring-sensor-tag  120   n,m  with coordinates  x =[x y z] and reader  100  number i is r (m,n),i  The distance measured between the given monitoring-sensor-tag  120   n,m  and reader  100  number i is h (m,n),i . The range measurement error is assumed to be a random variable w (m,n),i  with variance σ (m,n),i   2  h (m,n),i  can be expressed as follows: 
         [0000]        h   (m,n),i   =r   (m,n),i   +w   (m,n),i   (5)
 
         [0000]    Let us assume that the number (quantity) of readers  100  used to determine position (location) of the given monitoring-sensor-tag  120   n,m  is s. The distance (range) between the given monitoring-sensor-tag  120   n,m  and reader  100  number i, denoted as r (m,n),i  may be expressed as: 
         [0000]        r   (n,m),i =√{square root over (( x   i   −x ) 2 +( y   i   −y ) 2 +( z   i   −z ) 2 )} i= 1,2, . . . , s   (6)
 
         [0000]    We can therefore express the measured distance between the given monitoring-sensor-tag  120   n,m  and reader  100  number i as: 
         [0000]        h   (m,n),i =√{square root over (( x   i   −x ) 2 +( y   i   −y ) 2 +( z   i   −z ) 2 )}+ w   (m,n),i   (7)
 
         [0000]    In vector form, the vector  r   (n,m) ( x ) of distances (ranges) between the given monitoring-sensor-tag  120   n,m  with coordinates  x =[x y z] and the readers  100  where number i may be 1, 2, 3, . . . , s is: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       
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         [0000]    In vector form, the vector  h   (n,m)  of measured distances between the given monitoring-sensor-tag  120   n,m  and the readers  100  where number i may be 1, 2, 3, . . . , s is: 
         [0000]          h     (n,m)   =[h   (m,n),1   h   (m,n),2    . . . h   (m,n),s ] T   (9)
 
         [0000]    where T is a symbol for a vector or a matrix transpose.
 
In vector form, the vector  w   (n,m)  of measurement errors of the distances between the given monitoring-sensor-tag  120   n,m  and the readers  100  where number i may be 1, 2, 3, . . . , s is:
 
         [0000]          w     (n,m)   =[w   (m,n),1   w   (m,n),2    . . . w   (m,n),s ] T   (10)
 
         [0000]    We may express equation (5) in vector form, expressing the vector of distance measurements  h   (n,m)  as follows: 
         [0000]          h     (n,m) (   x   )=   r     (n,m) (   x   )+   w     (n,m)   (11)
 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       
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         [0000]    We need to estimate location coordinate x=[x y z] T  for each monitoring-sensor-tag  120   n,m  given the vector of distance measurements  h   (n,m)  between the given monitoring-sensor-tag  120   n,m  and the readers  100  where i may be 1, 2, 3, . . . , s. 
         [0418]    Alternatively (or in addition to), in conformity with the arrangement shown in  FIG. 14B , a single moving reader  100  number i may be used to obtain a series of coordinates (x i , y i , z i ) of this reader  100  number i, assuming the movement of this reader  100  number i may be controlled and its coordinates known, and as a function of time. 
         [0419]    There are numerous well-known methods (techniques and/or algorithms) to estimate  x  in equation (11). Based on the results of a calibration process described below, one may optionally use Nonlinear Least Squares (NLS) or Maximum Likelihood (ML) estimators among other available optimization techniques. 
         [0420]    An optional Nonlinear Least Squares (NLS) approach minimizes the least squares cost function derived from equation (7). It is a widely used and well-known method, that is discussed below. Based on equation (7) one may denote the NLS cost function C( x ) of the given monitoring-sensor-tag  120   n,m  position estimate x=[x y z] T  as: 
         [0000]    
       
         
           
             
               
                 
                   
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         [0000]    where:
       (x i , y i , z i ) are coordinates of Reader  100  number i, where i may be 1, 2, . . . , s; and   h (m,n),i  the measured distance between the given monitoring-sensor-tag  120   n,m  and reader  100  number i.
 
The NLS position estimate {circumflex over (x)} will correspond to the smallest value of the cost function C( x ):
       
 
         [0000]        {circumflex over (x)}=arg  min   x     C (   x   )  (14)
 
         [0000]    Levenberg-Marquardt Algorithm (LMA), Newton-Raphson Algorithm (NRA), Gauss-Newton Algorithm (GNA) are some methods widely used for solving optimization problem in equation (14). 
         [0423]    An optional Maximum Likelihood (ML) approach is a widely used and well-known method for solving non-linear equations by means of maximizing the Probability Density Function (PDF) of the function in question. 
         [0424]    A probability density function ρ( h   (n,m) ) for the vector of measured distances  h   (m,n)  from equation (11) may be expressed as: 
         [0000]    
       
         
           
             
               
                 
                   
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         [0000]    where R is the covariance matrix of  h   (n,m)  wherein R may be defined as: 
         [0000]        R=E {(   h     (n,m)   − r     (n,m) )(   h     (n,m)   − r     (n,m) ) T }=diag(σ 1   2 ,σ 2   2 , . . . ,σ s   2 )  (16)
 
         [0000]    where σ i   2  of is the variance of the range measurement error w (m,n),i  from above equation (6). R −1  is matrix inverse of the matrix R and |R| is determinant of matrix R
 
Maximization of the probability density function ρ( h   (n,m) ) of the vector of measured distances  h   (n,m)  in equation (12) may be expressed as the following minimization problem:
 
         [0000]        {circumflex over (x)} =arg min   x     C (   x   )  (17)
 
         [0000]    where C( x ) is a cost function of the position estimate  x =[x y z] T  of the given monitoring-sensor-tag  120   n,m  expressed as: 
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         [0000]    where:
       (x i , y i , z i ) are coordinates of Reader  100  number i, wherein number i may be 1, 2, . . . , s;   h (m,n),i  is the measured distance between the given monitoring-sensor-tag  120   n,m  and reader  100  number i; and     x =[x y z] T  is the position estimate of the given monitoring-sensor-tag  120   n,m.    
Levenberg-Marquardt Algorithm (LMA), Newton-Raphson Algorithm (NRA), Gauss-Newton Algorithm (GNA) are some methods widely used for solving optimization problem in equation (17).
       
 
         [0428]    Linear approaches for initial coordinate estimate. Many approaches have been used to convert non-linear equations (12) copied below: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       
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         [0000]    to set of linear equations, direct solution of which may provide a start point for an optimization process employed for finding the coordinates of the given monitoring-sensor-tag  120   n,m  in above equations (14) and (17). Some embodiments may employ widely described and well-known Linear Least Squares (LLS) and Weighted Linear Least Squares (WLLS) approaches in order to convert non-linear equation (12) into a linear forma; and then to find  x =[x y z] T  which is used as a start point for subsequent optimization processes in determining coordinates of the given monitoring-sensor-tag  120   n,m.    
         [0429]      FIG. 15  may depict a flow diagram illustrating steps in a method  1500  for non-invasive monitoring of a material-of-interest with one or more monitoring-sensor tag  120  using one or more readers  100 . 
         [0430]    Continuing discussing  FIG. 15 , in some embodiments method  1500  may comprise step  1530 ; wherein step  1530  may be a step of calibrating readers  100  that are to be used. That is in some embodiments, method  1500  may begin with step  1530  of calibrating the readers  100 . Reader  100  calibration in step  1530  may involve wireless communication between readers  100  and reference-sensor-tags  1102 . Recall, in some embodiments, reference-sensor-tags  1102  may have known locations (positions, coordinates). In some embodiments, reference-sensor-tags  1102  may comprise stress (deformation) sensor resistors (such as  700  and/or  703 ) with known parameters. In some embodiments, reference-sensor-tags  1102  may comprise capacitor-based relative permittivity sensors (such as  402 ,  404 ,  405 ,  406 ,  407 , and/or  408 ) with known parameters. In some embodiments, reference-sensor-tags  1102  may comprise one or more of: stress (deformation) sensor resistors (such as  700  and/or  703 ); and/or capacitor-based relative permittivity sensors (such as  402 ,  404 ,  405 ,  406 ,  407 , and/or  408 ) with known parameters. Such sensors of reference-sensor-tags  1102  may provide the one or more “calibration-readings” back to readers  100 ; which may then provide for various reference (or foundational) qualities to assist in calibrating readers  100 . In some embodiments, reference-sensor-tags  1102  sensors may also sense local (ambient) temperature to aid in temperature calibration while the local (ambient) temperature in vicinity of said sensors is known. 
         [0431]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1531 . In some embodiments, successful conclusion of step  1530  may then transition into step  1531 . In some embodiments, step  1531  may be a step of determining a location (i.e., position and/or coordinates) of the one or more readers  100 . Step  1531  may be accomplished by wireless communication between readers  100  and reference-sensor-tags  1102 , wherein locations of reference-sensor-tags  1102  may be known and thus locations of readers  100  may be determined relative to these known locations of reference-sensor-tags  1102 . 
         [0432]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1532 . In some embodiments, successful conclusion of step  1531  may then transition into step  1532 . In some embodiments, step  1532  may be a step of reader  100  interrogation of the one or more monitoring-sensor-tags  120  that are associated with the material-of-interest. In some embodiments, in this interrogation step  1532 , a number (quantity) of available one or more monitoring-sensor-tags  120  may be transmitted back to the readers  100  and determined. In some embodiments, in this interrogation step  1532 , “additional information” of the one or more monitoring-sensor-tags  120  may be transmitted back to the readers  100  and determined. In some embodiments, this “additional information” may comprise one or more of: identification information for a given monitoring-sensor-tag  120  that is transmitting (e.g., an ID for each monitoring-sensor-tag  120  that is transmitting); model number for the given monitoring-sensor-tag  120  that is transmitting; serial number for the given monitoring-sensor-tag  120  that is transmitting; manufacturer of the given monitoring-sensor-tag  120  that is transmitting; year of manufacture of the given monitoring-sensor-tag  120  that is transmitting; or a request for a security code associated with that given monitoring-sensor-tag  120  that is transmitting; a public security key; a cyclic redundancy check code for the given monitoring-sensor-tag  120  that is transmitting; a parity check code for the given monitoring-sensor-tag  120  that is transmitting; and receipt of a disable instruction for the given monitoring-sensor-tag  120  that is transmitting; wherein the given monitoring-sensor-tag  120  that is transmitting is selected from the one or more monitoring-sensor-tags  120 . 
         [0433]    The cyclic redundancy check code and/or the parity check code for the given monitoring-sensor-tag  120  that may be transmitting may be known approaches to generate additional data based on the transmitted information. That additional data, once received by the readers  100  and further analyzed by a processor  1801  (see e.g.,  FIG. 18 ) may be used to validate correct transmission of said transmitted information. 
         [0434]    The model number for the given monitoring-sensor-tag  120  that may be transmitting; the serial number for the given monitoring-sensor-tag  120  that may be transmitting; and/or the manufacturer of the given monitoring-sensor-tag  120  may be information used for identifying the type of the given monitoring-sensor-tag  120  to be used in subsequent steps including but not limited to calibration. 
         [0435]    Continuing discussing  FIG. 15 , in some embodiments, step  1532  may progress into step  1534  or into step  1533 . In some embodiments, method  1500  may comprise step  1533 . In some embodiments, step  1533  may be an authentication step, to ensure that only authorized readers  100  (and not some other RFID type of reading/scanning device) may be accessing the one or more monitoring-sensor-tags  120 . For example, and without limiting the scope of the present invention, in some embodiments, the one or more monitoring-sensor-tags  120  may not transmit useful information, such as the one or more readings, unless the given monitoring-sensor-tag  120  first receives a proper security code (e.g., password) from the given reader  100 . In some embodiments, the given monitoring-sensor-tag  120  may transmit a request for this security code to the readers  100 . In some embodiments, the given monitoring-sensor-tag  120  may transmit its public security key in addition for the request for the said security code to the readers  100 . In some embodiments, where step  1533  is required in method  1500 , successful completion of the authentication step  1533  may then transition into step  1534 . 
         [0436]    Some applications of method  1500  may not include step  1533 , in which case, step  1532  may transition into step  1534 . 
         [0437]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1534 . In some embodiments, step  1534  may follow step  1532  or may follow step  1533 . In some embodiments, step  1534  may be a step of determining locations (positions and/or coordinates) of the one or more monitoring-sensor-tags  120 . Such location determination may proceed via LPS (local positioning systems) techniques as discussed above in the  FIG. 14A  and  FIG. 14B  discussion. 
         [0438]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1535 . In some embodiments, step  1535  may follow step  1534 . In some embodiments, step  1535  may be a step of the reader  100  instructing (i.e., commanding and/or requesting) the one more monitoring-sensor-tags  120 . In some embodiments, such instructions from the readers  100  may initiate a process in the one or more monitoring-sensor-tags  120  such that the given monitoring-sensor-tag  120  may generate the one or more readings from their one or more sensors and then transmit the resulting one or more readings back to the readers  100  via the antennas  130  of the given monitoring-sensor-tag  120 . For example, and without limiting the scope of the present invention, the readers  100  may request a specific measurement type to provide information (one or more readings) that may correlate with specific state information of the given material-of-interest that may be monitored and/or tracked by using one or more monitoring-sensor-tags  120  attached to (associated with) the given material-of-interest. Recall the one or more readings from the sensors of the one or more monitoring-sensor-tags  120  may yield state information such as, but not limited to: structural integrity of a current state of the material-of-interest; structural integrity changes of the material-of-interest; pressure received at the material-of-interest; force received at the material-of-interest; stress received at the material-of-interest; torsion received at the material-of-interest; deformation received at the material-of-interest; temperature at some portion of the material-of-interest; positional changes of a given monitoring-sensor-tag  120  attached to the material-of-interest with respect to position of another monitoring-sensor-tag  120  attached to the material-of-interest, wherein the given monitoring-sensor-tag  120  and the other monitoring-sensor-tag are  120  selected from the one or more monitoring-sensor-tags  120  attached to the material-of-interest; or positional changes of at least one monitoring-sensor-tag  120  attached to the material-of-interest with respect to time, wherein the at least one monitoring-sensor-tag  120  is selected from the one or more monitoring-sensor-tags  120 . For example, and without limiting the scope of the present invention, the readers  100  may request a specific measurement type from a specific sensor type. For example, and without limiting the scope of the present invention, the readers  100  may request one or more readings from specific sensors, wherein the specific sensors may be identified by a sensor-specific-ID (e.g., a unique sensor number for that specific sensor). In some embodiments, the sensor-specific-ID (sensor number) may serve to choose a specific sensor from a number of sensors of a given monitoring-sensor-tag  120 . For example, and without limiting the scope of the present invention, as shown in  FIG. 8 , a number of different sensors may exist for a given monitoring-sensor-tag  120 . For example, and without limiting the scope of the present invention, the readers  100  may transmit an oscillator frequency division ratio to the given monitoring-sensor-tag  120 . For example, and without limiting the scope of the present invention, sensors (of monitoring-sensor-tags  120 ) may belong to different ring oscillator circuits; and such different ring oscillator circuits may be selected sequentially or in parallel. That is, any given independent ring oscillators in a given monitoring-sensor-tag  120  may be engaged either sequentially or in parallel. 
         [0439]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1536 . In some embodiments, step  1536  may follow step  1535 . Alternatively, in some embodiments, step  1536  may be a sub-step of step  1535 . In some embodiments, step  1536  may be a step of the readers  100  transmitting the “restart counting” command to the one or more monitoring-sensor-tags  120 . Recall RESTART_COUNT signal  931  of  FIG. 9  and the  FIG. 9  discussion above. A monitoring-sensor-tag  120  receiving RESTART_COUNT signal  931  may then cause that monitoring-sensor-tag  120  to transmit one or more of the following: their current value of their counter; “maximum count reached” bit; the measurement type (sensor type); the sensor-specific-ID; the sensor&#39;s one or more readings; and/or frequency division rate. 
         [0440]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1537 . In some embodiments, step  1537  may follow step  1536 . In some embodiments, step  1537  may be a step of determining if additional measurements to be taken from the sensors of the one or more monitoring-sensor-tags  120 . If yes, then method  1500  may progress back to step  1536 . If no, then method  1500  may progress to step  1538 . In some embodiments, criteria for evaluating step  1537  may comprise, but may not be limited to, either achieving the predetermined mathematical variance of the series of obtained measurements or reaching a pre-defined maximal number of measurements. 
         [0441]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1538 . In some embodiments, step  1538  may follow a “no” outcome of step  1537 . In some embodiments, step  1538  may be a step of determining if the reader  100  locations are to be re-determined per step  1531 . If yes, then method  1500  may progress back to step  1531 . If no, then method  1500  may progress to step  1539 . In some embodiments, criteria for evaluating step  1538  may be defined by the settings provided by the user, matching the type of environment in which the specific embodiment is used. For example, in the case of a static set of readers as related to patient  1328 , like the one depicted in  FIG. 13B , step  1538  may not be required. In case of a system, like the one shown in  FIG. 13C , comprising a translating-scan-member  1326  that may translate along a predetermined path of motion, step  1538  may be performed either each time or at predetermined time intervals to ensure that the location of the translating-scan-member  1326  is determined correctly. 
         [0442]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1539 . In some embodiments, step  1539  may follow a “no” outcome of step  1538 . In some embodiments, step  1539  may be a step of determining if different measurement types are be taken from the sensors of the one or more monitoring-sensor-tags  120 . If yes, then method  1500  may progress back to step  1535 . If no, then method  1500  may progress to step  1540 . In some embodiments, criteria for evaluating step  1539  may be provided by the settings in the specific embodiment. For example, if monitoring-sensor-tags  120  of different types are used (e.g., measuring stress, temperature, humidity, liquid penetration, etc.) step  1539  may determine that additional measurement types have to be performed. 
         [0443]    Continuing discussing  FIG. 15 , in some embodiments, method  1500  may comprise step  1540 . In some embodiments, step  1540  may follow a “no” outcome of step  1539 . In some embodiments, step  1540  may be a step of readers  100  transmitting “received monitoring-sensor-tag  120  transmissions.” In some embodiments, the received monitoring-sensor-tag  120  transmissions may comprise one or more of the following: the one or more readings; the sensor-specific-ID; the additional information; and/or any other information and/or data transmitted from antennas  130  of the one or more monitoring-sensor-tags  120 . In some embodiments, the readers  100  may transmit this “received monitoring-sensor-tag  120  transmissions” to processor  1801  (see e.g.,  FIG. 18 ) for processing and analysis. In some embodiments, the readers  100  may transmit this “received monitoring-sensor-tag  120  transmissions” to memory  1803 , where processor  1801  (see e.g.,  FIG. 18 ) may then access for processing and analysis. In some embodiments, the readers  100  may transmit this “received monitoring-sensor-tag  120  transmissions” to antenna-interface  1115 ; wherein antenna-interface  1115  may route (transmit) to memory  1803 , where processor  1801  (see e.g.,  FIG. 18 ) may then access for processing and analysis. In some embodiments, the readers  100  may transmit this “received monitoring-sensor-tag  120  transmissions” to antenna-interface  1115 ; wherein antenna-interface  1115  may route (transmit) to processor  1801  (see e.g.,  FIG. 18 ) which may then access the said “received monitoring-sensor-tag  120  transmissions” for processing and analysis. In some embodiments, the readers  100  may pre-process some of “received monitoring-sensor-tag  120  transmissions” via an electric circuit of the reader  100  prior to transmission to: antenna-interface  1115 , memory  1803 , or processor  1801 . 
         [0444]    Overall broadly speaking, calibration may mean adjusting precision based on known facts (i.e., known data and/or known information). For example, positioning a reference tag at a known distance before start of using a device may permit fine-tuning of the system. For example, it may be known what electromagnetic (EM) wave phase delay should be at a distance of 1 m (i.e., one meter). The extra phase which may be measured may be due to phase distortion, introduced by tag, antenna, reader  100 , cable and; may be filtered out (accounted for) thanks to a calibration process. 
         [0445]    It is natural that in the specific system  1800  there may be a need for more than one calibration method based on the type of monitoring-sensor-tags  120 , readers  100 , antennas  110  as well as other elements of the system  1800 . Below, for example, may describe one such possible calibration method  1600 . In some embodiments,  FIG. 16  may depict a flow diagram illustrating a method  1600  for calibrating the system  1800  (see  FIG. 18 ) based on one or more reference-sensor-tags  1102 . In some embodiments,  FIG. 16  may depict a flow diagram illustrating a method  1600  for calibrating one or more readers  100 . In some embodiments, step  1530  of method  1500  shown in  FIG. 15  may be method  1600 . That is, in some embodiments, method  1600  shown in  FIG. 16  may depict how step  1530  may proceed. In some embodiments, method  1600  may comprise steps: step  1680 , step  1681 , step  1682 , and step  1683 . 
         [0446]    Discussing  FIG. 16 , in some embodiments, step  1680  may choose a set of reference-sensor-tags  1102  to match a type and an environmental setting of used (or to be used) monitoring-sensor-tags  120 . As noted below, in order to filter out possible measurement distortions from the measurements and to fine-tune the system  1800 , the type of the reference-sensor-tags  1102  needs to match or to be as close as possible to the type of monitoring-sensor-tag  120 . 
         [0447]    Continuing discussing  FIG. 16 , in some embodiments, step  1681  may be a stage at which a calibration method and its settings are chosen based on the specific system  1800  in place, and based on the user-provided options and preferences. For example, and without limiting the scope of the present invention, a specific range of the reader  100  frequencies may be selected, reader  100  transmitting power may be adjusted, reader  100  transmitting mode can be selected, among other settings, during step  1681 . 
         [0448]    Determining range, using one of the techniques above, such as phase difference of arrival (PDoA), is based on measuring the phase difference of arrival φ of the electromagnetic (EM) wave emitted by reader  100 , wirelessly (e.g., backscattered) by a given monitoring-sensor-tag  120 , and received by reader  100 , according to the configuration of  FIG. 14A , as an example. 
         [0449]    Continuing discussing  FIG. 16 , in some embodiments, step  1682  may perform phase measurements of monitoring-sensor-tags  120 . For each reader  100  number α j  take N measurements of the phase φ(f s ) k   α     j     ,c     i    (where k=1 . . . N) between α j  and each reference-sensor-tag  1102  number c i  allocated to reader  100  number α j  in the software settings. The said phase measurements may be taken at a number of different frequencies f s  where s=1 . . . M. 
         [0450]    In some embodiments, instead of performing a predefined number N of phase measurements, a number of phase measurements may be limited by the number at which the mathematical variance of φ(f s ) k   α     j     ,c     i    falls below a predetermined value for each pair α j , c i  and each frequency f s  where s=1 . . . M. 
         [0451]    In some embodiments, the phase difference of arrival φ between the electromagnetic (EM) wave emitted by reader  100 , wirelessly (e.g., backscattered) by a given monitoring-sensor-tag  120 , and received by reader  100 , according to the configuration of  FIG. 14A  may be expressed as: 
         [0000]      φ( f   s ) k   α     j     ,c     i   =φ wave +φ reader +φ tag  
 
       Where: 
       [0452]    φ wave  is the phase difference due to the propagation of the emitted electromagnetic (EM) wave; φ reader  is the phase difference introduced by but not limited to reader  100 , antenna  110 , and cables connecting reader  100  and antenna  110 ; and φ tag  is the phase difference introduced by a given monitoring-sensor-tag  120 . 
         [0453]    Continuing discussing  FIG. 16 , in some embodiments, step  1683  calibration of reference-sensor-tags  1102  measurements may be processed as follows:
       For each reader  100  number α j  and each reference-sensor-tag  1102  number c i  allocated to the reader  100 , calculate:   Mean  φ (f s ) k   α     j     ,c     i    of the phase measurements φ(f s ) k   α     j     ,c     i    between α j  and c i , k=1 . . . N for each frequency f s  where s=1 . . . M;   Difference φ delta (f s ) k   α     j     ,c     i    between the calculated phase φ wave (f s ) k   α     j     ,c     i    and φ(f s ) k   α     j     ,c     i        where:       
 
         [0000]      φ delta ( f   s ) k   α     j     ,c     i   =φ wave ( f   s ) k   α     j     ,c     i   − φ ( f   s ) k   α     j     ,c     i     (20)
 
         [0000]    where φ wave (f s ) k   α     j     ,c     i    the phase difference, due to the propagation of the emitted electromagnetic (EM) wave, mentioned above, is calculated as: 
         [0000]    
       
         
           
             
               
                 
                   ϕ 
                   wave 
                 
                  
                 
                   ( 
                   
                     f 
                     s 
                   
                   ) 
                 
               
               
                 
                   a 
                   j 
                 
                 , 
                 
                   c 
                   i 
                 
               
             
             = 
             
               
                 ( 
                 
                   
                     4 
                      
                     π 
                      
                     
                         
                     
                      
                     
                       r 
                       
                         j 
                         , 
                         i 
                       
                     
                      
                     
                       f 
                       s 
                     
                   
                   c 
                 
                 ) 
               
                
               mod 
                
               
                   
               
                
               2 
                
               π 
             
           
         
       
     
         [0000]    where c is the speed of light constant, mod is modulo (remainder) function, and as r j,i  is the known distance (range) from reader  100  number α j  and reference-sensor-tag  1102  number c i . 
         [0458]    Thus, the correction φ delta (f s ) k   α     j     ,c     i    to be applied to the reported phase φ(f s ) k   α     j     ,c     i    has been calculated. 
         [0459]      FIG. 17  may depict a flow diagram for determining location of one or more monitoring-sensor-tags  120  associated with (e.g., attached to) the given material-of-interest.  FIG. 17  may depict method  1700 . In some embodiments, method  1700  may be a method for determining location of one or more monitoring-sensor-tags  120  associated with (e.g., attached to) the given material-of-interest. In some embodiments, method  1700  may provide additional details of step  1534  from  FIG. 15 . 
         [0460]    For example, and without limiting the scope of the present invention, method  1700  may be employed to determine locations of one or more monitoring-sensor-tags  120  located in or on: dental-filling  1001  ( FIG. 10A ); root-canal-cavity  1003  ( FIG. 10B ); root-canal-post  1004  ( FIG. 10B ); dental-crown  1005  ( FIG. 10B ); dental-implant  1007  ( FIG. 10C ); implant-post  1008  ( FIG. 10C ); and/or the like. 
         [0461]    For example, and without limiting the scope of the present invention, method  1700  may be employed to determine locations of one or more monitoring-sensor-tags  120  located in or on the given material-of-interest in the systems of  FIG. 13A ,  FIG. 13B , or  FIG. 13C . 
         [0462]    In some embodiments, method  1700  may comprise method  1600 , step  1772 , step  1773 , and step  1777 . See e.g.,  FIG. 17 . 
         [0463]    Continuing discussing  FIG. 17 , in some embodiments, method  1700  may comprise method  1600  as discussed above, which may be a calibration method. In some embodiments, method  1700  may begin with method  1600 . 
         [0464]    Continuing discussing  FIG. 17 , in some embodiments, method  1700  may comprise step  1772 . In some embodiments, successful calibration under method  1600  may then transition into step  1772 . In some embodiments, step  1772  may be a step of obtaining measurements for determining ranges (distance) of the one or more monitoring-sensor tags  120  between readers  100 . As mentioned before, one of well-known techniques for location and range (distance) measurement may include phase difference of arrival (PDoA); received signal strength indicator (RSSI); time of arrival (ToA); time of flight (ToF); and/or time difference of arrival (TDoA). For example, for the phase difference of arrival (PDoA) technique, the measurements may include phase difference of arrival. In some embodiments, such range measuring may be between each operational monitoring-sensor tag  120  selected from the one or more monitoring-sensor tags  120 ; and from a predetermined number (quantity) of operational readers  100 . In some embodiments, the predetermined number (quantity) of operational readers  100  may be selected by a user engaging with software settings; wherein the software may be non-transitorily stored in memory  1803 . In some embodiments, the predetermined number (quantity) of operational readers  100  may be those readers  100  closest to the given monitoring-sensor-tag  120 . In some embodiments, the predetermined number (quantity) of operational readers  100  may be readers  100  determined under method  1600 . In some embodiments of step  1772 , measurements for determining of the range (distance) between each monitoring-sensor-tag  120  to each reader  100  from the group of readers  100  allocated to the given monitoring-sensor-tag  120  may be performed. In some embodiments, measurements of phase difference of arrival (PDoA) φ(f s ) k   α     j     ,s     u    from each monitoring-sensor-tag  120  number s u  to each reader  100  number α j  in its vicinity may be performed. In some embodiments, “in its vicinity” may be dependent upon a frequency (or a wavelength) of wireless communication utilized by antennas  110  and/or antennas  130  for a given application (for a given use). For example, and without limiting the scope of the present invention, when radio waves may be used by antennas  110  and/or antennas  130 , then “in its vicinity” may be selected from the group of 1 mm (millimeter) to 50 meters or less. In some embodiments, for each reader  100  number α j  step  1772  may take M measurements of phase difference of arrival (PDoA) φ(f s ) k   α     j     ,s     u    (where k=1 . . . M) between reader  100  number α j  and each monitoring-sensor-tag  120  number s u  allocated to reader  100  number α j . The said phase measurements may be taken at a number of different frequencies f s  where s=1 . . . L. In some embodiments, as noted above, allocation of readers  100  to monitoring-sensor-tags  120  may be predetermined and/or set by a user engaging with the software setting of the software. 
         [0465]    Continuing discussing  FIG. 17  and step  1772  in particular, in some embodiments, the above range phase difference of arrival (PDoA) φ(f s ) k   α     j     ,s     u    measurements may be processed by calculating a mean and a variance for each of the frequencies f s  where s=1 . . . L. For example, and without limiting the scope of the present invention, for each reader  100  number α j  and each monitoring-sensor-tag  120  number s u  allocated to that reader  100 , calculate for each of the frequencies f s  where s=1 . . . L:
       Mean  φ (f s ) k   α     j     ,s     u    of the phase measurements φ(f s ) k   α     j     ,s     u    between α j  and s u , k=1 . . . M; and   Variance σ 2 (φ(f) k   α     j     ,s     u   ) of the phase measurements φ(f s ) k   α     j     ,s     u    between α j  and s u , k=1 . . . M.       
 
         [0468]    Continuing discussing  FIG. 17 , in some embodiments, method  1700  may comprise step  1773 . In some embodiments, step  1773  may follow step  1772 . In some embodiments, step  1773  may be a step of applying calibration-based corrections (adjustments) to the measurements and/or calculations of step  1772 . For example, and without limiting the scope of the present invention, if monitoring-sensor-tags  120  locations have not been determined (calculated), then step  1773  may apply correction φ delta (f s ) k   α     j     ,c     i    calculated in equation (20) during described calibration process of method  1600 , to the phase  φ (f s ) k   α     j     ,s     u    calculated above, such a corrected phase may be: 
         [0000]      φ corrected ( f   s ) k   α     j     ,s     u   = φ ( f   s ) k   α     j     ,s     u   +φ delta ( f   s ) k   α     j     ,c     i     (21)
 
         [0000]    wherein the reference-sensor-tags  1102  number c i  in equation (21) may be the one closest to reader  100  number α j . In some embodiments, the reference-sensor-tags  1102  number c i  in equation (21) may be the one closest in type to monitoring-sensor-tag  120  number s u    
         [0469]    In some embodiments, reader  100  may emit electromagnetic (EM) waves at a number of pre-set frequencies f s . It is well known and shown that it is possible to range estimate (distance) h k   α     j     ,s     u    between each reader  100  number α j  and each monitoring-sensor-tag  120  number s u  by: 
         [0000]    
       
         
           
             
               
                 
                   
                     h 
                     
                       
                         a 
                         j 
                       
                       , 
                       
                         s 
                         u 
                       
                     
                   
                   = 
                   
                     
                       c 
                       
                         4 
                          
                         π 
                       
                     
                      
                     
                       
                         Δϕ 
                         
                           
                             a 
                             j 
                           
                           , 
                           
                             s 
                             u 
                           
                         
                       
                       
                         Δ 
                          
                         
                             
                         
                          
                         
                           f 
                           
                             
                               a 
                               j 
                             
                             , 
                             
                               s 
                               u 
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   22 
                   ) 
                 
               
             
           
         
       
     
         [0470]    where Δö k   α     j     ,s     u    is a phase difference between two values of phase φ corrected (f s ) k   α     j     ,s     u    corresponding to two different frequencies from the set of frequencies f s , and Δf k   α     j     ,s     u    is the difference between the said two different frequencies. In some embodiments, equation (22) is used to calculate the range estimate (distance) h k   α     j     ,s     u    between each reader  100  number α j  and each monitoring-sensor-tag  120  number s u . Continuing discussing  FIG. 17 , in some embodiments, method  1700  may comprise step  1777 . In some embodiments, step  1777  may follow step  1773 . In some embodiments, step  1777  may be a step of (non-transitory) saving determined (calculated) locations for the one or more monitoring-sensor-tags  120  to memory  1803 . 
         [0471]    Note, in some embodiments, calculations carried out in methods  1500 ,  1600 , and/or  1700  may be carried out by processor  1801  (see e.g.,  FIG. 18 ). 
         [0472]      FIG. 18  may depict a block diagram of reader  100  (or of reader-and-calibration-member  1109 ), processor  1801 , memory  1803 , a display  1805 , a position-reference-member  1204 , and a material-of-interest  1828  with one or more monitoring-sensor-tags  120 . In some embodiments,  FIG. 18  may depict a system  1800  for non-invasive monitoring of material-of-interest  1828  with one or more monitoring-sensor tag  120  using one or more readers  100  (or using at least one reader-and-calibration-member  1109  with one or more readers  100 ). 
         [0473]    Continuing discussing  FIG. 18 , in some embodiments, system  1800  may comprise one or more monitoring-sensor-tags  120  and one or more readers  100 . In some embodiments, the one or more readers  100  and the one or more monitoring-sensor-tags  120  may be in wireless communications with each other. 
         [0474]    Continuing discussing  FIG. 18 , the one or more monitoring-sensor-tags  120  may be as discussed previously above for monitoring-sensor-tags  120 . For example, and without limiting the scope of the present invention, the one or more monitoring-sensor-tags  120  may be “attached to” material-of-interest  1828 , wherein “attached to” has been described above. 
         [0475]    Continuing discussing  FIG. 18 , the one or more readers  100  may be as discussed previously above for readers  100 . In some embodiments, each of the one or more readers  100  may comprise one or more second-antennas  110 ; whereas a term of “first-antennas  130 ” may be antennas of the one or more monitoring-sensor-tags  120 . In some embodiments, the one or more readers  100  using their one or more second-antennas  110  may transmits electromagnetic (EM) radiation (e.g., radio waves) of a predetermined characteristic. Such a transmission may be directed to the one or more monitoring-sensor-tags  120 , specifically to their first-antennas  130 . Such that first-antennas  130  (of the one or more monitoring-sensor-tags  120 ) may receive this electromagnetic (EM) radiation of the predetermined characteristic as an input. In some embodiments, this input may cause the at least one electric circuit  140  (of the one or more monitoring-sensor-tags  120 ) to take the one or more readings from the at least one sensor (e.g.,  202  and/or  203 ); and to then transmit the one or more readings using the first-antennas  130  back to the one or more second-antennas  110  of the one or more readers  100 . In some embodiments, at least one of the second-antennas  110  selected from the one or more second-antennas  110  then receives the one or more readings; and the one or more readers  100  or a device  1807  in communication with the one or more readers  100  may then use the one or more readings to determine a “current state” (as them term has been discussed previously) of material-of-interest  1828 . 
         [0476]    In some embodiments, material-of-interest  1828  shown in  FIG. 18  may be representative of any materials-of-interest discussed previously herein, such as, but not limited to: dental-filling  1001 ; root-canal-post  1004 ; dental-crown  1005 ; an article implantable within a body of an organism; the article attachable to the body of the organism; specific tissue of the organism; and/or the construction member. As noted, in some embodiments, the article may be selected from: a medical device; a tissue graft; a bone graft; an artificial tissue; a bolus with time-release medication; and/or a medication. As noted, in some embodiments, the medical device may be dental-implant  1007  and/or implant-post  1008 . As noted, in some embodiments, the organism may be a human, such as patient  1328 . As noted, in some embodiments, the tissue may be tooth  1000 , gum  1002 , and/or root-canal-cavity  1003  and/or any other tissue of the organism. 
         [0477]    Continuing discussing  FIG. 18 , in some embodiments, system  1800  may further comprise device  1807  that may be in communication with the one or more readers  100  and that may then use the one or more readings to determine a current state of material-of-interest  1828 . In some embodiments, this device  1807  may comprise processor  1801  and memory  1803 . In some embodiments, device  1807  may be a computing device and/or a computer. In some embodiments, processor  1801  may be in communication with the one or more second-antennas  110 . In some embodiments, disposed between processor  1801  and the one or more second-antennas  110  may be antenna-interface  1115 , as that component has been discussed previously. In some embodiments, antenna-interface  1115  may be in communication with both the one or more second-antennas  110  and processor  1801 . In some embodiments, memory  1803  may be in communication with processor  1801 . In some embodiments, memory  1803  may be in communication with processor  1801  as well as with antenna-interface  1115  and/or the one or more second-antennas  110 . In some embodiments, non-transitorily stored in memory  1803  may be code (i.e., the software) for instructing processor  1801  how to interpret the current state by processing the one or more readings received at the at least one of the second-antennas  110  selected from the one or more second-antennas  110 . In some embodiments, data; information, the one or more readings; measurement results; calculation results; the “additional information”; and/or the like may be non-transitorily stored in memory  1803 . 
         [0478]    Note, in some embodiments, instead of a separate device  1807  as noted above, each reader  100  may itself comprise antenna-interface  1115 , processor  1801 , and memory  1803 . Whereas, in other embodiments, device  1807  may be integrated with the one more readers  100 . 
         [0479]    In some embodiments, memory  1803  may store (hold) information on a volatile or non-volatile medium, and may be fixed and/or removable. In some embodiments, memory  1803  may include a tangible computer readable and computer writable non-volatile recording medium, on which signals are stored that define a computer program (i.e., the code or the software) or information to be used by the computer program. The recording medium may, for example, be hard drive, disk memory, flash memory, and/or any other article(s) of manufacture usable to record and store information (in a non-transitory fashion). In some embodiments, in operation, processor  1801  may cause(s) data (such as, but not limited to, information, the one or more readings; measurement results; calculation results; the “additional information”; and/or the like) to be read from the nonvolatile recording medium into a volatile memory (e.g., a random access memory, or RAM) that may allow for more efficient (i.e., faster) access to the information by processor  1801  as compared against the nonvolatile recording medium. Memory  1803  may be located in device  1807  and in communication with processor  1801 . See e.g.,  FIG. 18 . In some embodiments, processor  1801  may manipulate(s) the data and/or information within integrated circuit memory (e.g., RAM) and may then copy the data to the nonvolatile recording medium (e.g., memory  1803 ) after processing may be completed. A variety of mechanisms are known for managing data movement between the nonvolatile recording medium and the integrated circuit memory element, and the invention is not limited to any mechanism, whether now known or later developed. The invention is also not limited to a particular processing unit (e.g., processor  1801 ) or storage unit (e.g., memory  1803 ). 
         [0480]    Continuing discussing  FIG. 18 , in some embodiments of system  1800  the one or more second-antennas  110  may have known (or determinable) positional locations. As previously discussed, locations of the one or more readers  100  (or locations of the second-antennas  110 ) may be determined via wireless communications between the one or more readers  100  (via their one or more second-antennas  110 ) and one or more reference-sensor-tags  1102  (via their at least one fourth-antennas). And/or as previously discussed, locations of the one or more readers  100  (or locations of the second-antennas  110 ) may be determined via wireless communications between the one or more readers  100  (via their one or more second-antennas  110 ) and one or more position-reference-tag  1203  (via their at least one third-antennas). That is in some embodiments, system  1800  may further comprise one or more reference-sensor-tags  1102  and/or system  1800  may further comprise one or more position-reference-tag  1203 . See e.g.,  FIG. 18 . As discussed previously, reference-sensor-tags  1102  may be housed in reference-housing-member  1107 . As discussed previously, reference-sensor-tags  1102  may be fixed with respect to second-antennas  110 ; even in embodiments where the second-antennas  110  may be translating with respect to origin  1325  (e.g., the systems of  FIG. 13A  and of  FIG. 13C ) (because the reader-and-calibration-member  1109  housing the second-antennas  110  may be translating together as a unit). As previously discussed, in some embodiments, position-reference-tags  1203  may be housed in position-reference-member  1204 . As previously discussed, in some embodiments, position-reference-tags  1203  and position-reference-member  1204  may be stationary; i.e., fixed with respect to an origin  1325 ; even when second-antennas  110  may be translating as shown in  FIG. 13A  and in  FIG. 13C  (because the reader-and-calibration-member  1109  housing the second-antennas  110  may be translating while position-reference-member  1204  remains stationary). Note, in some embodiments of system  1800 , position-reference-member  1204  (with position-reference-tags  1203 ) may be optional or not included. In any event, because locations (positions) of second-antennas  110  (or readers  100 ) may be determinable and thus known; then processor  1801  running the code (i.e., the software or the computer program) non-transitorily stored in memory  1803  may be instructed by that code, using these known positional locations of the one or more second-antennas  110  and using communications from the first-antennas  130 , may then determine (calculate) positional locations of the one or more monitoring-sensor-tags  120 . 
         [0481]    Continuing discussing  FIG. 18 , in some embodiments, reader  100  may comprise the one or more second-antennas  110 ; one or more reference-sensor-tags  1102 ; and antenna-interface  1115 . In some embodiments, the one or more reference-sensor-tags  1102  may be fixed relative to the one or more second-antennas  110 . In some embodiments, reader  100  may comprise one or more reference-housing-member  1107 ; wherein each reference-housing-member  1107  may comprise the one or more reference-sensor-tags  1102 . Thus, reader  100  may function as reader-and-calibration-member  1109 ; which is why reader  100  in  FIG. 18  is also noted as reader-and-calibration-member  1109 . In some embodiments, one or more second-antennas  110  may have known (or determinable) positional locations relative to: a known origin (e.g., origin  1325 ), known reference-sensor-tags  1102  locations, and/or known position-reference-tag  1203  locations. 
         [0482]    In some embodiments, one or more readers  100  may be disposed within reader-and-calibration-member  1109  and the one or more second-antennas  110  may have known positional locations relative to: a known origin (e.g., origin  1325 ), known reference-sensor-tags  1102  locations, and/or known position-reference-tag  1203  locations. See e.g.,  FIG. 11A ,  FIG. 11B , and  FIG. 18 . 
         [0483]      FIG. 19A  may show, in general, how complex permittivity of a given material (including biologic materials) may vary according to changes in frequency.  FIG. 19A  may show two graphs depicting real and imaginary parts ∈ r ′ and ∈ r ″, respectively, of complex permittivity  ∈   r  as a function of alternating current (AC) frequency. In  FIG. 19A , real and imaginary parts ∈ r ′ and ∈ r ″, respectively, of complex permittivity  ∈   r  may be denoted on the vertical axis; while the frequency may be denoted on the horizontal axis. In  FIG. 19A , the real part, ∈ r ′, may also be denoted by reference numeral  1901 . In  FIG. 19A , the imaginary part, ∈ r ″, may also be denoted by reference numeral  1902 . 
         [0484]    The complex permittivity  ∈   r , which may be referred to as a complex dielectric constant, may be expressed as: 
         [0000]        ∈   r =∈ r ′−∈ r ″  (23)
 
         [0000]    where ∈ r ′ is a “real” permittivity, ∈ r ″ is an imaginary permittivity, and j is an imaginary unit. 
         [0485]      FIG. 19A  demonstrates that in some embodiments, to measure complex permittivity of a given material, then frequency may need to be varied. 
         [0486]    It should be noted that the “real” permittivity ∈ r ′, a real part of complex permittivity  ∈   r , may be referred to as the relative permittivity of the dielectric material ∈ r . 
         [0487]      FIG. 19B  may be a perspective view of a capacitor  1905  connected to an alternating current (AC) voltage source  1906 . Current  1910  may thus flow via capacitor  1905 . In some embodiments, this capacitor  1905  may comprise two substantially parallel plates  400  that may be separated by dielectric material  401 . In some embodiments, such plates  400  may be separated from each other by a distance of d. In some embodiments, plates  400  may be constructed from substantially conductive materials. 
         [0488]    It should be appreciated by those of ordinary skill in the relevant art that one may find current  1910  flowing via capacitor  1905  by: 
         [0000]    
       
         
           
             
               
                 
                   
                     I 
                     s 
                   
                   = 
                   
                     
                       V 
                       s 
                     
                     Z 
                   
                 
               
               
                 
                   ( 
                   24 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where V s  is a complex representation of the voltage of the alternating current (AC) voltage source  1906 , I s  is a complex representation of current  1910  flowing via capacitor  1905 , and Z is complex impedance of capacitor  1905 . 
         [0489]    It should be appreciated by those of ordinary skill in the relevant art that capacitor  1905  may be represented by a number of representative circuits.  FIG. 19C  may depict a schematic view of a possible capacitor representative circuit  1909  of capacitor  1905  from  FIG. 19B . Capacitor representative circuit  1909  may comprise of an ideal resistor  1907  and an ideal capacitor  1908 , connected in parallel, see e.g.,  FIG. 19C . 
         [0490]      FIG. 19D  may depict a schematic view of capacitor representative circuit  1909 , connected to the alternating current (AC) voltage source  1906 . 
         [0491]    Complex admittance Y of the capacitor  1905  may be expressed as: 
         [0000]    
       
         
           
             
               
                 
                   Y 
                   = 
                   
                     
                       1 
                       Z 
                     
                     = 
                     
                       
                         
                           j 
                            
                           
                               
                           
                            
                           ω 
                            
                           
                               
                           
                            
                           A 
                            
                           
                               
                           
                            
                           
                             ɛ 
                             0 
                           
                            
                           
                             ɛ 
                             r 
                           
                         
                         d 
                       
                       = 
                       
                         
                           
                             j 
                              
                             
                                 
                             
                              
                             ω 
                              
                             
                                 
                             
                              
                             A 
                              
                             
                                 
                             
                              
                             
                               
                                 ɛ 
                                 0 
                               
                                
                               
                                 ( 
                                 
                                   
                                     ɛ 
                                     r 
                                     ′ 
                                   
                                   - 
                                   
                                     j 
                                      
                                     
                                         
                                     
                                      
                                     
                                       ɛ 
                                       r 
                                       ″ 
                                     
                                   
                                 
                                 ) 
                               
                             
                           
                           d 
                         
                         = 
                         
                           
                             
                               j 
                                
                               
                                   
                               
                                
                               ω 
                                
                               
                                   
                               
                                
                               A 
                                
                               
                                   
                               
                                
                               
                                 ɛ 
                                 0 
                               
                                
                               
                                 ɛ 
                                 r 
                                 ′ 
                               
                             
                             d 
                           
                           + 
                           
                             
                               ω 
                                
                               
                                   
                               
                                
                               A 
                                
                               
                                   
                               
                                
                               
                                 ɛ 
                                 0 
                               
                                
                               
                                 ɛ 
                                 r 
                                 ″ 
                               
                             
                             d 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   25 
                   ) 
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     Y 
                     = 
                     
                       
                         1 
                         Z 
                       
                       = 
                       
                         
                           G 
                           + 
                           jB 
                         
                         = 
                         
                           
                             j 
                              
                             
                                 
                             
                              
                             ω 
                              
                             
                                 
                             
                              
                             C 
                           
                           + 
                           
                             1 
                             R 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   26 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where Z is complex impedance of capacitor  1905 , G and B are conductance and susceptance, respectively of capacitor  1905 , ω is the angular frequency of the alternating current (AC) voltage source  1906 , A is an area of each of the conductive plates  400 , d is a width of the dielectric material  401  between the conductive plates  400 , ∈ 0 ≈8.85·10 −12  F/m is vacuum permittivity constant, C is the capacitance of the ideal capacitor  1908  and R is the resistance of the ideal resistor  1907 . 
         [0492]    Based on equations (25) and (26) one may express real and imaginary parts ∈ r ′ and ∈ r ″, respectively, via real and imaginary components G and B, respectively, of the complex admittance Y: 
         [0000]    
       
         
           
             
               
                 
                   
                     ɛ 
                     r 
                     ′ 
                   
                   = 
                   
                     Bd 
                     
                       ω 
                        
                       
                           
                       
                        
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                     
                   
                 
               
               
                 
                   ( 
                   27 
                   ) 
                 
               
             
             
               
                 
                   
                     ɛ 
                     r 
                     ″ 
                   
                   = 
                   
                     Gd 
                     
                       ω 
                        
                       
                           
                       
                        
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                     
                   
                 
               
               
                 
                   ( 
                   28 
                   ) 
                 
               
             
           
         
       
     
         [0493]    Based on equations (25) and (26) one may express real and imaginary parts ∈ r ′ and ∈ r ″, respectively, via components C and R, respectively, of the possible representative circuit  1909  of capacitor  1905 : 
         [0000]    
       
         
           
             
               
                 
                   
                     ɛ 
                     r 
                     ′ 
                   
                   = 
                   
                     Cd 
                     
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                     
                   
                 
               
               
                 
                   ( 
                   29 
                   ) 
                 
               
             
             
               
                 
                   
                     ɛ 
                     r 
                     ″ 
                   
                   = 
                   
                     d 
                     
                       ω 
                        
                       
                           
                       
                        
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                        
                       R 
                     
                   
                 
               
               
                 
                   ( 
                   30 
                   ) 
                 
               
             
           
         
       
     
         [0494]    Thus,  FIG. 19B ,  FIG. 19C , and  FIG. 19D  may show how relatively simple circuits may be employed so that complex permittivity of a given material may be measured.  FIG. 19B ,  FIG. 19C , and  FIG. 19D  may demonstrate relationships between complex permittivity of a given material and the parameters of the electric elements, such as capacitors comprising the given material.  FIG. 19B ,  FIG. 19C , and  FIG. 19D  may also demonstrate how complex permittivity of a given material may be expressed via measuring parameters of the electric circuits comprising said capacitor. 
         [0495]      FIG. 19E  may show, in general, how complex permittivity of a given material (including biologic materials) may vary according to changes in excitation source as well as changes in frequency. Excitation sources (inputs) may be selected from one or more of: visible light, infrared (IR) light, ultraviolet (UV) light, electromagnetic (EM) radiation, ultrasonic sound, temperature, pH, and/or the like—of predetermined characteristics (e.g., predetermined frequency, wavelength, temperature, etc.). The pairs of complex permittivity values [∈′ r1 , ∈″ r1 ], [∈′ r1 , ∈″ r1 ], [∈′ r1 , ∈″ r1 ] shown in  FIG. 19E  may depict changes in complex permittivity of the same material under different excitation conditions. For example the graphs  1911 ,  1912  in  FIG. 19E  correspond to the pairs [E′ r1 , ∈″ r1 ] may be obtained without excitation sources. The graphs  1913 ,  1914  in  FIG. 19E  correspond to the pairs [∈ 2 , ∈″ r2 ] may be obtained when exposing a given material under test with infrared (IR) light of predetermined frequency. While, the graphs  1915 ,  1916  in  FIG. 19E  correspond to the pairs [∈′ r3 , ∈″ r3 ] may be obtained when applying infrared (IR) light of yet another frequency to that same given material. A significance of using various predetermined excitation sources, of predetermined characteristics, may be in obtaining a more specific response or a more complete response, which could be then used to identify various conditions of the given material under test better rather than without using excitation sources. 
         [0496]      FIG. 19F  may be a view of a capacitor  1905  connected to an alternating current (AC) voltage source  1906 , wherein dielectric material  401 , disposed between opposing capacitor plates  400  of capacitor  1905 , may be exposed to one or more types of excitation sources, of predetermined characteristics. Current  1910  may flow via capacitor  1905 . In some embodiments, this capacitor  1905  may comprise two substantially parallel plates  400  that may be separated by dielectric material  401 . In some embodiments, plates  400  may be constructed from substantially conductive materials. In some embodiments dielectric material  401  may be subjected to external excitation sources including, but not limited to, infrared (IR) light source  1917 , LED light source  1918 , ultraviolet (UV) light source  1919 , and/or sonic or ultrasonic sound source  1920 —all of predetermined characteristics. As is conventional, LED may be one or more light emitting diodes. LED light source  1919  may emit visible light, IR light, UV light, and/or the like. And  1921  in  FIG. 19F  may be array-of-excitation-sources  1921  which may house one or more of: IR light source  1917 , LED light source  1918 , UV light source  1919 , and/or sonic or ultrasonic sound source  1920 . In some embodiments, in application, dielectric material  401  may be material-of-interest  2201  and/or implant  2431 . 
         [0497]      FIG. 20A  may depict a schematic block diagram of complex-monitoring-sensor-tag  2020  comprising a complex-impedance-sensor  2010 . In some embodiments, any given monitoring-sensor-tag  120  may be replaced with a given complex-monitoring-sensor-tag  2020 . In some embodiments, a given complex-monitoring-sensor-tag  2020  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , complex-impedance-measurement-circuit  2011 , and complex-impedance-sensor  2010 . In some embodiments, processing circuitry  204  may be in communication with complex-impedance-measurement-circuit  2011 . In some embodiments, processing circuitry  204  may be in communication with wireless-receiver-and-transmitter  207 . In some embodiments, complex-impedance-measurement-circuit  2011  may be in communication with complex-impedance-sensor  2010 . 
         [0498]    In some embodiments, complex-impedance-measurement-circuit  2011  may measure the complex impedance of complex-impedance-sensor  2010  to quantify a current state reading of material-of-interest (such as material-of-interest  2201  or of implant  2431 ) that complex-monitoring-sensor-tag  2020  may be attached to. In some embodiments, complex-impedance-measurement-circuit  2011  may interpret, calculate, and/or measure inputs received at the complex impedance of complex-impedance-sensor  2010  to quantify a current state reading of material-of-interest (such as material-of-interest  2201  or of implant  2431 ) that complex-monitoring-sensor-tag  2020  may be attached to. In some embodiments, processing circuitry  204  may control complex-impedance-measurement-circuit  2011  and process the one or more readings (the obtained results) received by complex-impedance-sensor  2010 , for radio-frequency transmission (or for other electromagnetic transmission); e.g., via wireless-receiver-and-transmitter  207 . In some embodiments, wireless-receiver-and-transmitter  207  may transmit the one or more readings (the obtained results) to reader  100 . In some embodiments, wireless-receiver-and-transmitter  207  may receive instructions from reader  100  using electromagnetic (EM) waves; such as, but not limited to radio wavelength electromagnetic (EM) waves. See e.g.,  FIG. 20A . 
         [0499]    In some embodiments, monitoring-sensor-tag  120  shown in  FIG. 1B  may be complex-monitoring-sensor-tag  2020 . In such embodiments, complex-monitoring-sensor-tag  2020  may comprise at least one antenna  130  and at least one electric circuit  140 ; which may be in communication with each other. In some such embodiments, at least one antenna  130  (of complex-monitoring-sensor-tag  2020 ) may comprise wireless-receiver-and-transmitter  207 . In some embodiments, at least one electric circuit  140  (of complex-monitoring-sensor-tag  2020 ) may comprise processing circuitry  204 . In some embodiments, at least one electric circuit  140  (of complex-monitoring-sensor-tag  2020 ) may comprise processing circuitry  204  and complex-impedance-measurement-circuit  2011 . In some embodiments, at least one electric circuit  140  (of complex-monitoring-sensor-tag  2020 ) may comprise processing circuitry  204 , complex-impedance-measurement-circuit  2011 , and complex-impedance-sensor  2010 . See e.g.,  FIG. 20A ,  FIG. 20B ,  FIG. 25A ,  FIG. 25B ,  FIG. 25C ,  FIG. 25D , and  FIG. 1B . 
         [0500]      FIG. 20B  may depict a schematic block diagram of complex-monitoring-sensor-tag  2020  comprising a complex-impedance-sensor  2010 , similar to that as shown in  FIG. 20A , but wherein in  FIG. 20B , complex-monitoring-sensor-tag  2020  may further comprise array-of-excitation-sources  1921 . In some embodiments array-of-excitation-sources  1921  may comprise and/or house one or more: IR light source  1917 , LED light source  1918 , UV light source  1919 , and/or a sonic or ultrasonic sound source  1920 ; wherein such sources of external excitation emit of a predetermined characteristic (e.g., predetermined frequency/wavelength). In some embodiments, the one or more external excitation sources of array-of-excitation-sources  1921  may be in electrical communication with one or more of complex-impedance-measurement-circuit  2011  and/or processing circuitry  204 . In some embodiments, the one or more external excitation sources of array-of-excitation-sources  1921  may be controlled by one or more of complex-impedance-measurement-circuit  2011  and/or processing circuitry  204 . See e.g.,  FIG. 20B . 
         [0501]    In some embodiments, wireless-receiver-and-transmitter  207  may be known as the “at least one antenna” and/or as the “at least one different antenna.” In some embodiments, the at least one antenna may be a given wireless-receiver-and-transmitter  207 . In some embodiments, the at least one different antenna may be a given wireless-receiver-and-transmitter  207 . In some embodiments, the at least one antenna, the at least one different antenna, and/or wireless-receiver-and-transmitter  207  may be a type of excitation source, emitting electromagnetic (EM) radiation (e.g., radio waves) of a predetermined frequency. 
         [0502]    In some embodiments, the at least one electric circuit may be processing circuitry  204  and/or complex-impedance-measurement-circuit  2011 . In some embodiments, the at least one different electric circuit may be processing circuitry  204  and/or complex-impedance-measurement-circuit  2011 . 
         [0503]    In some embodiments, the at least one sensor may be a given complex-impedance-sensor  2010 . In some embodiments, the at least one different sensor may be a given complex-impedance-sensor  2010 . 
         [0504]      FIG. 21A  may depict a schematic block diagram of a resistor  2103  with resistance R L  and a load  2101  with complex impedance Z connected serially to the alternating current (AC) voltage source  1906 . It should be appreciated by those of ordinary skill in the relevant art that one may find the value of the complex impedance Z by: 
         [0000]    
       
         
           
             
               
                 
                   Z 
                   = 
                   
                     
                       R 
                       L 
                     
                      
                     
                       
                         V 
                         2 
                       
                       
                         
                           V 
                           1 
                         
                         - 
                         
                           V 
                           2 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   31 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where V 1  is a complex representation of the voltage of the alternating current (AC) voltage source  1906  measured at point  2104  and V 2  is a complex representation of the voltage across the load  2101  measured at point  2105 . In some embodiments, point  2104  and point  2105  may be disposed at opposite sides of resistor  2103 . Thus,  FIG. 21A  may depict a circuit where complex impedance may be determined. 
         [0505]      FIG. 21B  may depict a schematic block diagram of resistor  2103  with resistance R L  and with load  2101  with complex impedance Z connected serially to an alternating current (AC) current source  2106 . The value of the complex impedance Z may be determined using equation (31) noted above. Thus,  FIG. 21B  may depict a circuit where complex impedance may be determined. 
         [0506]    Basic techniques for measuring complex impedance or complex permittivity may be understood in the relevant art. See e.g., J. Walworth, “Measuring complex impedances at actual operating levels,” Electronics, 47(15), pp. 117-118, 1974; and see also R. H. Johnson, N. M. Pothecary, M. P. Robinson, A. W. Preece and C. J. Railton, “Simple non-invasive measurement of complex permittivity,” in Electronics Letters, vol. 29, no. 15, pp. 1360-1361, 22 Jul. 1993. 
         [0507]      FIG. 22A  may depict a schematic view of an example of a two electrode electrochemical impedance spectroscopy (EIS) application.  FIG. 22A  may depict a schematic block diagram of a two-electrode complex impedance measuring technique using alternating current (AC) current source  2106  and two electrodes  2203  attached to material-of-interest  2201 . Voltage meter  2205  measures complex voltage across the two electrodes  2203 . In some embodiments, material-of-interest  2201  may be at least a portion of tissue (e.g., skin) or a cell of patient  1328 . 
         [0508]      FIG. 22B  may depict a schematic view of an example of a four electrode electrochemical impedance spectroscopy (EIS) application.  FIG. 22B  may depict a schematic block diagram of a four-electrode complex impedance measuring technique using alternating current (AC) current source  2106 , two electrodes  2203  attached to the material-of-interest  2201 , and another two electrodes  2204  attached to the material-of-interest  2201 . Voltage meter  2205  measures complex voltage across the two electrodes  2204 . 
         [0509]    Basic techniques for measuring impedance using two or four electrodes may be understood in the relevant art. See e.g., Millard, S. G. “Reinforced concrete resistivity measurement techniques,” In: Proceedings of Institution of Civil Engineers, Part 2: Research and Theory, pp. 91:71-88, 1991. 
         [0510]      FIG. 23A  may be a top view of a four-terminal probe; with substantially parallel regions of a conductive surface of type “G”  2309  and  2310 . In some embodiments, conductive surface of type “G”  2309  and  2310  may be mounted to the substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “G”  2309  and  2310  may be constructed from electrically conductive materials of construction. In some embodiments, conductive surface of type “G”  2309  and  2310  may be arranged in pairs of substantially parallel rows in a spiral fashion with substrate  403  disposed between or/and under such substantially parallel rows; for example, and without limiting the scope of the present invention, arranged as conductive wires in concentric circles on a dielectric substrate. 
         [0511]    In some embodiments,  FIG. 23A  may depict at least a portion of a four terminal complex impedance measuring sensor. In some embodiments,  FIG. 23A  may be at least a portion of complex-impedance-sensor  2010 . 
         [0512]      FIG. 23B  may be a top view of a four-terminal probe; with substantially parallel regions of a conductive surface of type “H”  2311  and  2312 . In some embodiments, conductive surface of type “H”  2311  and  2312  may be mounted to the substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “H”  2311  and  2312  may be constructed from electrically conductive materials of construction. In some embodiments, conductive surface of type “H”  2311  and  2312  may be arranged in pairs of substantially parallel rows in a spiral fashion with substrate  403  disposed between or/and under such substantially parallel rows; for example, and without limiting the scope of the present invention, arranged as conductive wires in concentric circles on a dielectric substrate. 
         [0513]    In some embodiments,  FIG. 23B  may depict at least a portion of a four terminal complex impedance measuring sensor. In some embodiments,  FIG. 23B  may be at least a portion of complex-impedance-sensor  2010 . 
         [0514]      FIG. 23C  may be a top view of two four-terminal probes; with regions of a conductive surface of type “I”  2313  and  2314 ; and with regions of a conductive surface of type “J”  2315  and  2316 . In some embodiments, conductive surface of type “I”  2313  and  2314  and conductive surface of type “J”  2315  and  2316  may each be mounted to a same substrate  403 . In some embodiments, substrate  403  may be a dielectric material. In some embodiments, conductive surface of type “I”  2313  and  2314  and conductive surface of type “J”  2315  and  2316  may be constructed from electrically conductive materials of construction. In some embodiments, conductive surface of type “I”  2313  and  2314  may be arranged in concentric circles (e.g., in a bull&#39;s eye fashion) with substrate  403  disposed between such concentric circles. In some embodiments, conductive surface of type “J”  2315  and  2316  may be arranged in concentric squares with substrate  403  disposed between or/and under such concentric squares. 
         [0515]    In some embodiments,  FIG. 23C  may depict at least a portion of a four terminal complex impedance measuring sensor. In some embodiments,  FIG. 23C  may be at least a portion of complex-impedance-sensor  2010 . 
         [0516]      FIG. 23D  may be a view of two different opposed terminal probes; of regions of a conductive surface of type “K”  2317  mounted to material-of-interest  2201 . In some embodiments, conductive surface of type “K”  2317  may be constructed from electrically conductive materials of construction. In some embodiments a plurality of infrared (IR) light sources of type “A”  2318  and/or a plurality of infrared (IR) light sources of type “B”  2319  may be affixed in the vicinity (e.g., within a predetermined distance in some embodiments) of the two different opposed terminal probes; of regions of a conductive surface of type “K”  2317  in order to expose material-of-interest  2201  to external excitation source, such as, but not limited to, infrared (IR) light. In some embodiments the plurality of infrared (IR) light sources of type “A”  2318  or the plurality of infrared (IR) light sources of type “B”  2319  may be of a predetermined frequency (e.g., monochromatic). In some embodiments, the plurality of infrared (IR) light sources of type “A”  2318  or the plurality of infrared (IR) light sources of type “B”  2319  may be of coherent emission type. In some embodiments, a plurality of infrared (IR) light source of type “B”  2319  may be present to expose material-of-interest  2201  to external excitation source of a different type or characteristic from infrared (IR) light source of type “A”  2318 . For example, and without limiting the scope of the present invention, such as an IR light source of a different frequency than the IR light source of type “A”  2318 . In some embodiments, the plurality of infrared (IR) light source of type “B”  2319  may be visible light sources, ultraviolet (UV) light sources, and/or ultrasonic (or sonic) sound sources. 
         [0517]    In some embodiments, the plurality of infrared (IR) light sources of type “A”  2318  or/and the plurality of infrared (IR) light sources of type “B”  2319  may be part of the array-of-excitation-sources  1921 . 
         [0518]    It can be appreciated by one skilled in the art that the plurality of infrared (IR) light sources of type “A”  2318 , the plurality of infrared (IR) light sources of type “B”  2319 , visible light sources, ultraviolet light sources, or ultrasonic sound sources should be powered by an electric energy source. 
         [0519]      FIG. 24A  may depict a system for non-invasive monitoring of a material-of-interest (e.g., material-of-interest  2201 , not shown in  FIG. 24A ) with lattice-of-sensors  2423  that may be in and/or on patient  1328 . In some embodiments, reader-and-calibration-member  1109  may be used to interrogate lattice-of-sensors  2423 . In some embodiments, lattice-of-sensors  2423  may comprise a plurality of complex-monitoring-sensor-tags  2020  (e.g., first-sensor-tag  2420  and/or second-sensor-tag  2421 ) and/or a plurality of sensors (e.g., first-sensor-type  2406  and/or second-sensor-type  2407 ), see  FIG. 24B  for details of lattice-of-sensors  2423 . In some embodiments, material-of-interest  2201  may be on or in patient  1328 . In some embodiments, material-of-interest  2201  may be at least a portion of tissue (e.g., skin) or a cell of patient  1328 . In some embodiments, lattice-of-sensors  2423  may be located under cast-or-bandage  2401 . In some embodiments, lattice-of-sensors  2423  may be on an interior-surface  2402  of cast-or-bandage  2401  (see  FIG. 24D  for interior-surface  2402  of cast-or-bandage  2401 ). 
         [0520]    In some embodiments, cast-or-bandage  2401  may be: a cast, a bandage, a dressing, gauze, a compression bandage, an elastic bandage, tape, kinesiology tape, KT tape, elastic therapeutic tape, strapping, webbing, a patch, a sling, a splint, or the like. 
         [0521]    In some embodiments, lattice-of-sensors  2423  may be in physical contact with at least portions of material-of-interest  2201 , and thus lattice-of-sensors  2423  may be used to monitor material-of-interest  2201  for various states of material-of-interest  2201 . For example, and without limiting the scope of the present invention, the system and/or configuration shown in  FIG. 24A  may be used and useful for monitoring healing of wounds and/or of skin of patient  1328 ; wherein material-of-interest  2201  may a portion of the wound and/or the skin. 
         [0522]    For example, and without limiting the scope of the present invention, the system and/or configuration shown in  FIG. 24A  may be used and useful for monitoring status (state) (e.g., healing or recovery progression) of tissue of interest (e.g., a region of skin) in a burn victim. 
         [0523]    For example, and without limiting the scope of the present invention, the system and/or configuration shown in  FIG. 24A  may be used and useful for monitoring status (state) (e.g., healing or recovery progression) of tissue of interest (e.g., a region of skin) of various skin cancers. 
         [0524]    For example, and without limiting the scope of the present invention, the system and/or configuration shown in  FIG. 24A  may be used and useful for monitoring status (state) (e.g., healing or recovery progression) of tissue of interest (e.g., a region of skin) of various dermatological issues, such as, but not limited to, rashes. 
         [0525]    Changes in measured complex impedance of material-of-interest  2201  (e.g., tissue, cells, or a cell), may also indicate problems in patient  1328 , such as, but not limited to, infection, decay, dying tissue, and/or the like. 
         [0526]    And recall such monitoring and/or tacking via the system and/or configuration of  FIG. 24A  may be done non-invasively and with minimal to no ionizing radiation. 
         [0527]    Continuing discussing  FIG. 24A , in some embodiments, reader-and-calibration-member  1109  may be handheld. In some embodiments, reader-and-calibration-member  1109  may be mobile. In some embodiments, reader-and-calibration-member  1109  may be used to interrogate lattice-of-sensors  2423 . In some embodiments, reader-and-calibration-member  1109  may provide the necessary electrical power lattice-of-sensors  2423  needs to operate; and this may only occur when reader-and-calibration-member  1109  and lattice-of-sensors  2423  are sufficiently close to each other. 
         [0528]    Continuing discussing  FIG. 24A , in some embodiments, device  1807  may be selected from: a computer, a personal computer, a desktop computer, a handheld computer, a laptop computer, a tablet computer, a smartphone, a mobile computing device, a computing device, or the like. 
         [0529]    Continuing discussing  FIG. 24A , in some embodiments, reader-and-calibration-member  1109  and device  1807  may be in communication with each other. In some embodiments, reader-and-calibration-member  1109  and device  1807  may be in wired communication with each other. In some embodiments, reader-and-calibration-member  1109  and device  1807  may be in wireless communication with each other. In some embodiments, reader-and-calibration-member  1109  and device  1807  may be attached to each other. In some embodiments, reader-and-calibration-member  1109  and device  1807  may be flexibly attached to each other. In some embodiments, reader-and-calibration-member  1109  and device  1807  may be in removable connection with each other. 
         [0530]    In some embodiments,  FIG. 24A  may depict a system for non-invasive monitoring of a material-of-interest (e.g., material-of-interest  2201 , not shown in  FIG. 24A ) with one or more complex-monitoring-sensor-tags  2020  that may be in and/or on patient  1328 . 
         [0531]    In some embodiments, lattice-of-sensors  2423  shown in  FIG. 24A  may be replaced with lattice-of-sensors  1023  or with monitoring-sensor-tag  120 . Compare  FIG. 24A  against  FIG. 13C . 
         [0532]      FIG. 24B  may depict structural details of a given lattice-of-sensors  2423 . In some embodiments, lattice-of-sensors  2423  may be a lattice framework of a plurality of sensor-tags, such as complex-monitoring-sensor-tag  2020  and/or of monitoring-sensor-tag  120 . In some embodiments, this plurality of sensor-tags may comprise sensor-spacing  2426 ; wherein sensor-spacing  2426  may be spacing between two adjacent sensor-tags of lattice-of-sensors  2423 . In some embodiments, sensor-spacing  2426  may be predetermined and fixed. In some embodiments, sensor-spacing  2426  may be predetermined, fixed, and substantially equal between various adjacent sensor-tags. In some embodiments, sensor-spacing  2426  may be predetermined, fixed, and may be different distances, but known, between various adjacent sensor-tags. 
         [0533]    Continuing discussing  FIG. 24B , in some embodiments, lattice-of-sensors  2423  may comprise a first-sensor-tag  2420 , a lattice framework of a plurality of sensors, and a second-sensor-tag  2421 . In some embodiments, first-sensor-tag  2420  may be a complex-monitoring-sensor-tag  2020  (see e.g.,  FIG. 20A ,  FIG. 20 ,  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and/or  FIG. 25D ). Continuing discussing  FIG. 24B , in some embodiments, second-sensor-tag  2421  may be another complex-monitoring-sensor-tag  2020  (see e.g.,  FIG. 20A ,  FIG. 20 ,  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and/or  FIG. 25D ). Continuing discussing  FIG. 24B , in some embodiments, this plurality of sensors may comprise first-sensor-type(s)  2406  and/or second-sensor-type(s)  2407 . In some embodiments, first-sensor-type  2406  may be a complex-impedance-sensor  2010 . In some embodiments, a given first-sensor-type  2406  may be a complex-impedance-sensor  2010 ; such as shown in  FIG. 22A ,  FIG. 22B ,  FIG. 23A ,  FIG. 23B ,  FIG. 23C , or  FIG. 23D . In some embodiments, second-sensor-type  2407  may be another complex-impedance-sensor  2010 . In some embodiments, a given second-sensor-type  2407  may be another complex-impedance-sensor  2010 ; such as shown in  FIG. 22A ,  FIG. 22B ,  FIG. 23A ,  FIG. 23B ,  FIG. 23C , or  FIG. 23D . Continuing discussing  FIG. 24B , in some embodiments, first-sensor-type  2406  and second-sensor-type  2407  may be of different types of complex-impedance-sensors  2010  with respect to each other. In some embodiments, first-sensor-type  2406  and/or second-sensor-type  2407  may in communication with first-sensor-tag  2420 . In some embodiments, first-sensor-type  2406  and/or second-sensor-type  2407  may in electrical communication with first-sensor-tag  2420 . In some embodiments, first-sensor-type  2406  and/or second-sensor-type  2407  may in communication with second-sensor-tag  2421 . In some embodiments, first-sensor-type  2406  and/or second-sensor-type  2407  may in electrical communication with second-sensor-tag  2421 . In some embodiments, sensor-spacing  2426  may be spacing between adjacent sensors. In some embodiments, sensor-spacing  2426  may be spacing between first-sensor-type  2406  and an adjacent second-sensor-type  2407 . In some embodiments, within a given lattice-of-sensors  2423  positions of sensor-tags (e.g., first-sensor-tag  2420  and/or second-sensor-tag  2421 ) and positions of the plurality of sensors (e.g., first-sensor-type  2406  and/or second-sensor-type  2407 ) may be fixed with respect to each other. In some embodiments, within a given lattice-of-sensors  2423  positions of sensor-tags (e.g., first-sensor-tag  2420  and/or second-sensor-tag  2421 ) and positions of the plurality of sensors (e.g., first-sensor-type  2406  and/or second-sensor-type  2407 ) may be known with respect to each other. See e.g.,  FIG. 24B . Compare  FIG. 24B  against  FIG. 10D . Compare lattice-of-sensors  2423  against lattice-of-sensors  1023 . 
         [0534]    Continuing discussing  FIG. 24B , in some embodiments, lattice-of-sensors  2423  may comprise first-sensor-tag  2420 , and the lattice framework of the plurality of sensors. 
         [0535]    Continuing discussing  FIG. 24B , in some embodiments, first-sensor-type  2406  may be a complex-monitoring-sensor-tag  2020 . In some embodiments, second-sensor-type  2407  may be a complex-monitoring-sensor-tag  2020 . 
         [0536]    In some embodiments, a given lattice-of-sensors  2423  may be arranged in a one dimensional, two dimensional, or three dimensional configuration. In some embodiments, a given lattice-of-sensors  2423  may be arranged in mesh configuration. In some embodiments, a given lattice-of-sensors  2423  may be arranged in lattice configuration. 
         [0537]    In some embodiments, at least a portion of a given lattice-of-sensors  2423  may be substantially covered in a protective covering (e.g., a protective film). 
         [0538]    In some embodiments, a system for non-invasive monitoring of tissue (e.g., tissue-of-interest), may comprise at least one lattice-of-sensors (such as lattice-of-sensors  2423  and/or lattice-of-sensors  1023 ). 
         [0539]    In some embodiments, material-of-interest  2201  may be a tissue-of-interest. In some embodiments, material-of-interest  1028  may be a tissue-of-interest. In some embodiments, material-of-interest  1828  may be a tissue-of-interest. In some embodiments, the tissue-of-interest may be tissue from an organism, such as, but not limited to, an organ, a portion of an organ, a bone, a joint, skin, a region of skin, a body part, a portion of a body part, portions thereof, combinations thereof, and/or the like. 
         [0540]    In some embodiments, at least a portion of the at least one lattice-of-sensors  2423  may be proximate to the tissue-of-interest. See e.g.,  FIG. 24A , wherein the tissue-of-interest may be skin or tissue beneath cast-or-bandage  2401 . In some embodiments, this proximate distance may be predetermined. In some embodiments, at least a portion of the at least one lattice-of-sensors  2423 , with or without a protective covering (layer or film), may be in direct physical contact to the tissue-of-interest; e.g., when the tissue-of-interest may be skin. 
         [0541]    In some embodiments, upon the at least one antenna (e.g., a given wireless-receiver-and-transmitter  207 ) of a given lattice-of-sensors  2423 , receiving electromagnetic (EM) radiation of a predetermined characteristic (e.g., from a reader-and-calibration-member  1109  or from a reader  100 ) as an input, this input may cause the at least one circuit (e.g., processing circuitry  204  and/or complex-impedance-measurement-circuit  2011 ) to take one or more readings from the at least one sensor of the first-sensor-tag (complex-monitoring-sensor-tag  2020  and/or monitoring-sensor-tag  120 ) or from at least one sensor (first-sensor-type  2406  and/or  2407 ) selected from the plurality of sensors; and to then transmit the one or more readings using the at least one antenna; wherein this transmitted one or more readings may be received back at reader-and-calibration-member  1109  or at reader  100 . 
         [0542]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one lattice-of-sensors  2423  may further comprise second-sensor-tag  2421 . In some embodiments, second-sensor-tag  2421  may comprise at least one different electric circuit (e.g., processing circuitry  204  and/or complex-impedance-measurement-circuit  2011 ) comprising at least one different sensor (e.g., complex-impedance-sensor  2010 ). In some embodiments, second-sensor-tag  2421  may comprise the at least one different antenna (e.g., which may be a given wireless-receiver-and-transmitter  207 ) which may be in communication with the at least one different electric circuit. In some embodiments, the plurality of sensors (of lattice-of-sensors  2423 ) may be in communication with second-sensor-tag  2421 ; wherein at least a different portion of the plurality of sensors may be physically connected to second-sensor-tag  2421 . In some embodiments, upon the at least one different antenna receiving the electromagnetic (EM) radiation of the predetermined characteristic as the input, this input may cause the at least one different circuit to take one or more different readings from the at least one different sensor of the second-sensor-tag  2421  or from at least one sensor selected from the plurality of sensors (such as, first-sensor-type  2406  and/or second-sensor-type  2407 ); and to then transmit the one or more different readings using the at least one different antenna; back to a reader-and-calibration-member  1109  and/or a reader  100 . See e.g.,  FIG. 24B ,  FIG. 24A , and  FIG. 24C . 
         [0543]    In some embodiments, the system for non-invasive monitoring of tissue, the plurality of sensors of lattice-of-sensors  2423  may be disposed between first-sensor-tag  2420  and second-sensor-tag  2421 . See e.g.,  FIG. 24B . 
         [0544]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one sensor of the first-sensor-tag  2420 , the at least one different sensor of the second-sensor-tag  2421 , or the plurality of sensors may be selected from one or more of: a capacitive-based sensor, a resistance-based sensor, an inductance-based sensor, a permittivity based sensor, a complex permittivity based sensor, and/or a complex impedance based sensor. 
         [0545]    In some embodiments, the system for non-invasive monitoring of tissue, the one or more readings (e.g., from the at least one sensor of first-sensor-tag  2420  and/or from the plurality of sensors); and/or the one or more different readings (e.g., from the at least one different sensor of second-sensor-tag  2421  and/or from the plurality of sensors) may convey information of one or more of: inductance, capacitance, resistance, permittivity, complex permittivity, or complex impedance. Such information received at a given reader-and-calibration-member  1109  and/or a given reader  100 , wherein this received information may then be stored and/or interpreted. 
         [0546]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one different circuit of first-sensor-tag  2420  may be given a complex-impedance-measurement-circuit  2011  and/or a given processing circuitry  204 . 
         [0547]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one different circuit of second-sensor-tag  2421  may be given a complex-impedance-measurement-circuit  2011  and/or a given processing circuitry  204 . 
         [0548]    Continuing discussing  FIG. 24B , in some embodiments, the system for non-invasive monitoring of tissue, each sensor selected from the plurality of sensors (e.g., first-sensor-type  2406  and/or second-sensor-type  2407 ) of lattice-of-sensors  2423  may comprises its own measurement circuit and its own antenna; which may communicate with reader-and-calibration-member  1109  and/or with reader  100 . 
         [0549]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one lattice-of-sensors  2423  may further comprise array-of-excitation-sources  1921 . In some embodiments, array-of-excitation-sources  1921  may house and/or may comprise one or more excitation sources that may emit energy of a predetermined frequency. In some embodiments, the one or more excitation sources may be IR light source  1917 , LED light source  1918 , UV light source  1919 , and/or sonic or ultrasonic sound source  1920 . In some embodiments, the one or more excitation sources of the array-of-excitation-sources  1921  may be in electrical communication with the at least one electric circuit (e.g., processing circuitry  204  and/or complex-impedance-measurement-circuit  2011  of complex-monitoring-sensor-tag  2020  which may be first-sensor-tag  2420 ). In some embodiments, the one or more excitation sources of the array-of-excitation-sources  1921  may be in electrical communication with the at least one different electric circuit (e.g., processing circuitry  204  and/or complex-impedance-measurement-circuit  2011  of complex-monitoring-sensor-tag  2020  which may be second-sensor-tag  2421 ). Recall, in some embodiments, lattice-of-sensor  2423  (e.g.,  FIG. 24B ) may comprise first-sensor-tag  2420  and/or second-sensor-tag  2421 ; and that first-sensor-tag  2420  and/or second-sensor-tag  2421  may be a given complex-monitoring-sensor-tag  2020  as shown in  FIG. 20B  and/or as shown  FIG. 25D , both with a given array-of-excitation-sources  1921 . 
         [0550]    In some embodiments, the system for non-invasive monitoring of tissue, the input (e.g., from reader-and-calibration-member  1109  and/or from reader  100 ) may further cause the at least one circuit (e.g., of first-sensor-tag  2420 ) to cause the one or more excitation sources to emit the energy of the predetermined frequency. In some embodiments, the input (e.g., from reader-and-calibration-member  1109  and/or from reader  100 ) may further cause the at least one different circuit (e.g., of second-sensor-tag  2421 ) to cause the one or more excitation sources to emit the energy of the predetermined frequency. In some embodiments, the input (e.g., from reader-and-calibration-member  1109  and/or from reader  100 ) may power the one or more excitation sources to emit the energy of the predetermined frequency. 
         [0551]      FIG. 24C  may depict another system for non-invasive monitoring of material-of-interest (e.g., material-of-interest  2201 , not shown in  FIG. 24C ) with lattice-of-sensors  2423  that may be in and/or on patient  1328 . In  FIG. 24C , reader-and-calibration-member  1109  and device  1807  may be as noted in the above  FIG. 24A  discussion; and in the earlier discussions of reader-and-calibration-member  1109  and of device  1807 . In some embodiments, reader-and-calibration-member  1109  may be used to interrogate lattice-of-sensors  2423 . As noted above (see e.g.,  FIG. 24B ), in some embodiments, lattice-of-sensors  2423  may comprise a plurality of complex-monitoring-sensor-tags  2020  (e.g., first-sensor-tag  2420  and/or second-sensor-tag  2421 ) and/or a plurality of sensors (e.g., first-sensor-type  2406  and/or second-sensor-type  2407 ). In some embodiments, material-of-interest  2201  may be on or in patient  1328 . In some embodiments, material-of-interest  2201  may be at least a portion of tissue (e.g., skin) or a cell of patient  1328 . In some embodiments, lattice-of-sensors  2423  may be located under article-in-lattice-contact  2430 . In some embodiments, lattice-of-sensors  2423  may be on an interior-surface  2402  of article-in-lattice-contact  2430  (see  FIG. 24D  for interior-surface  2402  of article-in-lattice-contact  2430 ). 
         [0552]    In some embodiments, article-in-lattice-contact  2430  may be: a bra, a sports bra, a brazier, an undergarment, underwear, an article of clothing, a cast, a bandage, cast-or-bandage  2401 , a dressing, gauze, a compression bandage, an elastic bandage, tape, kinesiology tape, elastic therapeutic tape, strapping, webbing, a patch, a sling, a splint, sutures, a medical device, an implant  2431 , a breast implant, and/or the like. As a category, article-in-lattice-contact  2430  may be broader and encompass cast-or-bandage  2401 . As shown in  FIG. 24C , article-in-lattice-contact  2430  may be bra. 
         [0553]    Specifically as shown in  FIG. 24C , article-in-lattice-contact  2430  may be a bra, wherein lattice-of-sensors  2423  may be disposed on an inside surface of the bra (e.g., interior-surface  2402 ), such that at least portions of lattice-of-sensors  2423  may be in physical contact with skin of the breasts of patient  1328 ; wherein complex impedance of the contacted skin may then may be monitored and provide state (status) information of not only such contacted skin, but also of breast tissue beneath such skin; wherein such monitoring may be facilitated by reader-and-calibration-member  1109  interrogating lattice-of-sensors  2423 , with results and/or data displayed and/or stored on device  1807 . By using such a system and/or configuration breast health may be monitored and/or tracked, non-invasively and with minimal to no ionizing radiation, in real time or near real time. By using such a system and/or configuration breast cancers and/or breast tumors may be monitored and/or tracked, non-invasively and with minimal to no ionizing radiation, in real time or near real. 
         [0554]    Similarly, the system and/or configuration shown in  FIG. 24C  may be adapted such that article-in-lattice-contact  2430  is underwear with lattice-of-sensors  2423  in physical contact with skin of testicles, such that testicle health, testicular tumors, and/or testicular cancers may be monitored and/or tracked, non-invasively and with minimal to no ionizing radiation, in real time or near real time. 
         [0555]    In some embodiments,  FIG. 24C  may depict a system for non-invasive monitoring of a material-of-interest (e.g., material-of-interest  2201 , not shown in  FIG. 24C ) with one or more complex-monitoring-sensor-tags  2020  that may be in and/or on patient  1328 . 
         [0556]    In some embodiments,  FIG. 24C  may depict the system for non-invasive monitoring of tissue with one or more complex-monitoring-sensor-tags  2020  that may be in and/or on patient  1328 . 
         [0557]    In some embodiments, the system for non-invasive monitoring of tissue, the system further may comprise at least one reader-and-calibration-member  1109 , see e.g.,  FIG. 24A  and  FIG. 24C . In some embodiments, at least one reader-and-calibration-member  1109  may have its own antenna (e.g., antenna  110 , see e.g.,  FIG. 11A ,  FIG. 11B , and/or  FIG. 11C ). In some embodiments, the at least one reader-and-calibration-member  1109  may provide the electromagnetic (EM) radiation of the predetermined characteristic as the input. In some embodiments, the at least one reader-and-calibration-member  1109  may be in radio communication with the at least one lattice-of-sensors  2423 . See e.g.,  FIG. 24A  and  FIG. 24C . In some embodiments, the at least one reader-and-calibration-member  1109  may receive the one or more readings and/or the one or more different readings. 
         [0558]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one reader-and-calibration-member  1109  may comprises one or more reference-sensor-tags  1102 . See e.g.,  FIG. 11A ,  FIG. 11B , and/or  FIG. 11C . 
         [0559]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one reader-and-calibration-member  1109  may be in communication (wireless or wired communication) with a computing device  1807 . In some embodiments, this computing device  1807  may perform one or more of the following with the one or more readings (and/or with the one or more different readings): interprets, displays, and/or stores (e.g., in memory  1803  of device  1807 ). See e.g.,  FIG. 24A ,  FIG. 24C , and  FIG. 18 . 
         [0560]    In some embodiments, the system for non-invasive monitoring of tissue, the system may further comprise computing device  1807 . See e.g.,  FIG. 24A  and  FIG. 24C . In some embodiments, computing device  1807  may be mobile, as in a smartphone, tablet, laptop, and/or the like. 
         [0561]    In some embodiments,  FIG. 24D  may depict a portion of cast-or-bandage  2401 . In some embodiments,  FIG. 24D  may depict an interior-surface  2402  side of cast-or-bandage  2401 . In some embodiments,  FIG. 24D  may show lattice-of-sensors  2423  against interior-surface  2402  of cast-or-bandage  2401 . In some embodiments, at least portions of lattice-of-sensors  2423  may in physical contact with portions of interior-surface  2402 . In some embodiments, at least portions of lattice-of-sensors  2423  may physically attached to portions of interior-surface  2402 . In some embodiments, at least portions of lattice-of-sensors  2423  and portions of interior-surface  2402  may be integral with each other. See e.g.,  FIG. 24D . 
         [0562]    In some embodiments,  FIG. 24D  may depict a portion of article-in-lattice-contact  2430 . In some embodiments,  FIG. 24D  may depict an interior-surface  2402  side of article-in-lattice-contact  2430 . In some embodiments,  FIG. 24D  may show lattice-of-sensors  2423  against interior-surface  2402  of article-in-lattice-contact  2430 . In some embodiments, at least portions of lattice-of-sensors  2423  may in physical contact with portions of interior-surface  2402 . In some embodiments, at least portions of lattice-of-sensors  2423  may physically attached to portions of interior-surface  2402 . In some embodiments, at least portions of lattice-of-sensors  2423  and portions of interior-surface  2402  may be integral with each other. See e.g.,  FIG. 24D . 
         [0563]    In some embodiments, article-in-lattice-contact  2430  may be a medical device and/or an implant, such as in implant  2431 . See e.g.,  FIG. 24E .  FIG. 24E  may depict a diagram showing at least one lattice-of-sensors  2423  that may be imbedded within a given implant  2431 . For example, and without limiting the scope of the present invention, implant  2431  may be: a breast implant, a medical device, a pump, a medication release bolus, an artificial organ, an artificial bone, an artificial limb, an artificial joint, mesh (e.g., hernia repair mesh), combinations thereof, and/or the like. 
         [0564]      FIG. 24F  may depict a diagram showing at least one lattice-of-sensors  2423  that may be mounted on (attached to) an external surface of a given implant  2431 . 
         [0565]    In some embodiments, at least one lattice-of-sensors  2423  may be partially located on an external surface of implant  2431  and may also be partially located within the implant  2431 , i.e., a combination of  FIG. 24E  and  FIG. 24F . 
         [0566]    In some embodiments, the system for non-invasive monitoring of tissue, this system may further comprise at least one article-in-lattice-contact  2430 . In some embodiments, the at least one lattice-of-sensors  2423  may be attached to the article-in-lattice-contact  2430  such that the at least the portion of the at least one lattice-of-sensors  2423  may be proximate to the tissue-of-interest, when the article-in-lattice-contact  2430  may be removably affixed to a portion of a body. See e.g.,  FIG. 24A ,  FIG. 24C ,  FIG. 24D ,  FIG. 24E , and  FIG. 24F . In some embodiments, implant  2431  may be a type of article-in-lattice-contact  2430 . 
         [0567]    In some embodiments, the at least one lattice-of-sensors  2423  may be attached to an interior-surface of the article-in-lattice-contact  2430  such that the at least a portion of the at least one lattice-of-sensors  2423  may be proximate to the tissue-of-interest, when the article-in-lattice-contact  2430  may be removably affixed to a portion of a body. See e.g.,  FIG. 24A ,  FIG. 24C , and  FIG. 24D . 
         [0568]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one lattice-of-sensors  2423  may be located within the article-in-lattice-contact  2430  such that the at least a portion of the at least one lattice-of-sensors  2423  may be proximate to the article-in-lattice-contact  2430 , when the article-in-lattice-contact  2430  may be removably affixed to a portion of a body. See e.g.,  FIG. 24E  where implant  2431  may be a type of article-in-lattice-contact  2430 . 
         [0569]    In some embodiments, the system for non-invasive monitoring of tissue, the at least one lattice-of-sensors  2423  may be located on an exterior surface of the article-in-lattice-contact  2430  such that the at least a portion of the at least one lattice-of-sensors  2423  may be proximate to the article-in-lattice-contact  2430  and/or proximate to the tissue-of-interest, when the article-in-lattice-contact  2430  may be removably affixed to a portion of a body. See e.g.,  FIG. 24F  where implant  2431  may be a type of article-in-lattice-contact  2430 . 
         [0570]    In some embodiments, the system for non-invasive monitoring of tissue, the one or more readings (e.g., from first-sensor-tag  2420  and/or from the plurality of sensors); and/or the one or more different readings (e.g., from second-sensor-tag  2421  and/or from the plurality of sensors) may be transmitted through the at least one article-in-lattice-contact  2430  while the article-in-lattice-contact  2430  may be removably affixed to the portion of the body. 
         [0571]      FIG. 25A  may depict additional details of a given complex-monitoring-sensor-tag  2020 , in a schematic block diagram. In some embodiments, complex-monitoring-sensor-tag  2020  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , complex-impedance-measurement-circuit  2011 , and complex-impedance-sensor  2010 , see e.g.,  FIG. 20A . In some embodiments, complex-impedance-sensor  2010  may comprise at least two electrodes  2203 , that may be in physical contact with material-of-interest  2201 , as shown in  FIG. 25A . 
         [0572]    Here in  FIG. 25A , additional details of complex-impedance-measurement-circuit  2011  may be shown. In some embodiments, complex-impedance-measurement-circuit  2011  may comprise resistor  2103 , point  2104 , point  2105 , analyzer  2511 , and variable-frequency-AC-source  2512 . In some embodiments, resistor  2103  may be disposed between point  2104  and point  2105 . In some embodiments, analyzer  2511  may be in communication with processing circuitry  204 , point  2104 , and point  2105 . In some embodiments, variable-frequency-AC-source  2512  may be in communication with processing circuitry  204 , wireless-receiver-and-transmitter  207 , point  2104 , and an electrode  2203  of complex-impedance-sensor  2010 . 
         [0573]    In some embodiments, variable-frequency-AC-source  2512  may perform a function of an alternating current (AC) voltage source (e.g.,  1906 ) or of an alternating current (AC) current source (e.g.,  2106 ). In some embodiments, variable-frequency-AC-source  2512  may change its frequency. Therefore, determination of the complex impedance or complex permittivity of material-of-interest  2201  may be done at different frequencies, as may be desirable. In some embodiments, processing circuitry  204  may control variable-frequency-AC-source  2512 . In some embodiments, wireless-receiver-and-transmitter  207  may control variable-frequency-AC-source  2512 . In some embodiments, both processing circuitry  204  and wireless-receiver-and-transmitter  207  may control variable-frequency-AC-source  2512 . In some embodiments, the carrier frequency of wireless-receiver-and-transmitter  207  may be supplied to variable-frequency-AC-source  2512 . Techniques for designing and building variable frequency alternating current (AC) sources are well understood in the relevant art and should be appreciated by those of ordinary skill in the relevant art. 
         [0574]    Continuing discussing  FIG. 24A , in some embodiments, analyzer  2511  may be used to determine the value of the complex impedance or complex permittivity of material-of-interest  2201 . 
         [0575]    It should be appreciated by those of ordinary skill in the relevant art that one of the ways that one may find the value of the complex impedance Z of material-of-interest  2201  may be in using equation (31) which will be copied below for convenience: 
         [0000]    
       
         
           
             
               
                 
                   Z 
                   = 
                   
                     
                       R 
                       L 
                     
                      
                     
                       
                         V 
                         2 
                       
                       
                         
                           V 
                           1 
                         
                         - 
                         
                           V 
                           2 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   31 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where V 1  is a complex representation of the voltage at point  2104  and V 2  is a complex representation of the voltage at point  2105 , and R L  is the known impedance of resistor  2103 . 
         [0576]    The analyzer  2511  may be connected to point  2104  and point  2105 . The known impedance of resistor  2103  may be available in digital or analogue form to analyzer  2511  as well in order to obtain the value of the complex impedance Z of material-of-interest  2201 . 
         [0577]    Basic techniques for realizing a variant of analyzer  2511  may be understood in the relevant art. See e.g., J. Walworth, “Measuring complex impedances at actual operating levels,” Electronics, 47(15), pp. 117-118, 1974. 
         [0578]      FIG. 25B  may depict additional details of a given complex-monitoring-sensor-tag  2020 , in a schematic block diagram. In some embodiments, complex-monitoring-sensor-tag  2020  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , complex-impedance-measurement-circuit  2011 , and complex-impedance-sensor  2010 , see e.g.,  FIG. 20A . In some embodiments, complex-impedance-sensor  2010  may comprise at least two electrodes  2203 , that may be in physical contact with material-of-interest  2201 , as shown in  FIG. 25B . 
         [0579]    Here in  FIG. 25B , additional details of complex-impedance-measurement-circuit  2011  may be shown. In some embodiments, complex-impedance-measurement-circuit  2011  may comprise resistor  2103 , point  2104 , point  2105 , analyzer  2511 , and frequency-divider  2513 . In some embodiments, resistor  2103  may be disposed between point  2104  and point  2105 . In some embodiments, analyzer  2511  may be in communication with processing circuitry  204 , point  2104 , and point  2105 . In some embodiments, frequency-divider  2513  may be in communication with processing circuitry  204 , wireless-receiver-and-transmitter  207 , point  2104 , and an electrode  2203  of complex-impedance-sensor  2010 . 
         [0580]    Continuing discussing  FIG. 25B , in some embodiments, frequency-divider  2513  may be programmable. In some embodiments, frequency-divider  2513  may perform a function of controllably reducing the carrier frequency of wireless-receiver-and-transmitter  207 , supplied to frequency-divider  2513 . Therefore, determination of the complex impedance or complex permittivity of material-of-interest  2201  may be done at different frequencies, as may be desired. In some embodiments, processing circuitry  204  may control frequency-divider  2513 . In some embodiments, wireless-receiver-and-transmitter  207  may control frequency-divider  2513 . In some embodiments, both processing circuitry  204  and wireless-receiver-and-transmitter  207  may control frequency-divider  2513 . As a result, frequency range from zero up to the carrier frequency of wireless-receiver-and-transmitter  207 , may be produced by frequency-divider  2513  in order to determine the complex impedance or complex permittivity of material-of-interest  2201  at different frequencies. Techniques for designing programmable frequency dividers are well understood in the relevant art and should be appreciated by those of ordinary skill in the relevant art. 
         [0581]    In some embodiments, variable-frequency-AC-source  2512  and/or frequency-divider  2513  may be examples of means-to-supply-variable-frequencies to material-of-interest  2201 . 
         [0582]    In some embodiments, the system for non-invasive monitoring of tissue, the complex-impedance-measurement-circuit  2011  (which may be a component of the at least one electric circuit of first-sensor-tag  2420 ) may comprise a variable-frequency-AC-source  2512  that may use a frequency supplied by the at least one antenna (e.g., a wireless-receiver-and-transmitter  207 ), so that complex impedance may be measured within a predetermined ranges of frequencies. See e.g.,  FIG. 25A . That is, the complex-monitoring-sensor-tag  2020  shown in  FIG. 25A  may be first-sensor-tag  2420  of lattice-of-sensors  2423  shown in  FIG. 24B . 
         [0583]    In some embodiments, the system for non-invasive monitoring of tissue, the complex-impedance-measurement-circuit  2011  (which may be a component of the at least one electric circuit of first-sensor-tag  2420 ) may comprise a frequency-divider  2513  that may use a frequency supplied by the at least one antenna (e.g., a wireless-receiver-and-transmitter  207 ), to measure complex impedance within a range of frequencies. See e.g.,  FIG. 25B . That is, the complex-monitoring-sensor-tag  2020  shown in  FIG. 25B  may be first-sensor-tag  2420  of lattice-of-sensors  2423  shown in  FIG. 24B . 
         [0584]    See e.g., complex-monitoring-sensor-tag  2020  of  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and/or  FIG. 25D . In some embodiments, first-sensor-tag  2420  (see e.g.,  FIG. 24B ) may be a complex-monitoring-sensor-tag  2020  (see e.g.,  FIG. 20A ,  FIG. 20B ,  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and  FIG. 25D ). In some embodiments, the at least one antenna of first-sensor-tag  2420  may be wireless-receiver-and-transmitter  207  of complex-monitoring-sensor-tag  2020 . 
         [0585]    In some embodiments, the system for non-invasive monitoring of tissue, the complex-impedance-measurement-circuit  2011  (which may be a component of the at least one different electric circuit of second-sensor-tag  2421 ) may comprise a variable-frequency-AC-source  2512  that may use a frequency supplied by the at least one different antenna (e.g., a wireless-receiver-and-transmitter  207 ), so that complex impedance may be measured within a predetermined ranges of frequencies. See e.g.,  FIG. 25A . That is, the complex-monitoring-sensor-tag  2020  shown in  FIG. 25A  may be second-sensor-tag  2421  of lattice-of-sensors  2423  shown in  FIG. 24B . 
         [0586]    In some embodiments, the system for non-invasive monitoring of tissue, the complex-impedance-measurement-circuit  2011  (which may be a component of the at least one different electric circuit of second-sensor-tag  2421 ) may comprise frequency-divider  2513  that may use a frequency supplied by the at least one different antenna (e.g., a wireless-receiver-and-transmitter  207 ), to measure complex impedance within a range of frequencies. See e.g.,  FIG. 25B . That is, the complex-monitoring-sensor-tag  2020  shown in  FIG. 25B  may be second-sensor-tag  2421  of lattice-of-sensors  2423  shown in  FIG. 24B . 
         [0587]    See e.g., complex-monitoring-sensor-tag  2020  of  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and/or  FIG. 25D . In some embodiments, second-sensor-tag  2421  (see e.g.,  FIG. 24B ) may be a complex-monitoring-sensor-tag  2020  (see e.g.,  FIG. 20A ,  FIG. 20B ,  FIG. 25A ,  FIG. 25B ,  FIG. 25C , and  FIG. 25D ). In some embodiments, the at least one different antenna of second-sensor-tag  2421  may be wireless-receiver-and-transmitter  207  of complex-monitoring-sensor-tag  2020 . 
         [0588]      FIG. 25C  may depict additional details of a given complex-monitoring-sensor-tag  2020 , in a schematic block diagram. In some embodiments, complex-monitoring-sensor-tag  2020  may comprise wireless-receiver-and-transmitter  207 , processing circuitry  204 , complex-impedance-measurement-circuit  2011 , and complex-impedance-sensor  2010 , see e.g.,  FIG. 20A . In some embodiments, complex-impedance-sensor  2010  may comprise at least two electrodes  2203 , that may be in physical contact with material-of-interest  2201 , as shown in  FIG. 25C . 
         [0589]    Here in  FIG. 25C , additional details of complex-impedance-measurement-circuit  2011  may be shown. In some embodiments, complex-impedance-measurement-circuit  2011  may comprise variable resistor  2514 , point  2104 , point  2105 , analyzer  2511 , and variable-frequency-AC-source  2512 . In some embodiments, variable resistor  2514  may be disposed between point  2104  and point  2105 . In some embodiments, analyzer  2511  may be in communication with processing circuitry  204 , point  2104 , point  2105 , and variable resistor  2514 . In some embodiments, variable-frequency-AC-source  2512  may be in communication with processing circuitry  204 , wireless-receiver-and-transmitter  207 , point  2104 , and an electrode  2203  of complex-impedance-sensor  2010 . 
         [0590]    Continuing discussing  FIG. 25C , in some embodiments, variable resistor  2514  may be programmable. In some embodiments, analyzer  2511  may perform a function of controlling the impedance of variable resistor  2514 . Therefore, determination of the complex impedance or complex permittivity of material-of-interest  2201  may be done at different impedance levels of variable resistor  2514 , as may be desired. In some embodiments, processing circuitry  204  may control variable resistor  2514 . In some embodiments, analyzer  2511  may control variable resistor  2514 . In some embodiments, both processing circuitry  204  and analyzer  2511  may control variable resistor  2514 . Techniques for designing variable resistors are well understood in the relevant art and should be appreciated by those of ordinary skill in the relevant art. 
         [0591]      FIG. 25D  may depict additional details of the complex-monitoring-sensor-tag  2020  of  FIG. 20B , in a schematic block diagram. In some embodiments, complex-monitoring-sensor-tag  2020  shown in  FIG. 25D  may be substantially similar to the complex-monitoring-sensor-tag  2020  shown in  FIG. 25C , except in  FIG. 25D , complex-monitoring-sensor-tag  2020  may further comprise array-of-excitation-sources  1921 . As noted, in some embodiments, array-of-excitation-sources  1921  may house and/or may comprise one or more excitation sources, such as, but not limited to, IR light source  1917 , LED light source  1918 , UV light source  1919 , and/or sonic sound source  1920 , as shown in  FIG. 20B . Continuing discussing  FIG. 25D , in some embodiments, the one or more excitation sources of array-of-excitation-sources  1921  may be in electrical communication with processing circuitry  204 . In some embodiments, the one or more excitation sources of array-of-excitation-sources  1921  may be controlled by processing circuitry  204 . In some embodiments, processing circuitry may control the one or more excitation sources of array-of-excitation-sources  1921 . In some embodiments, processing circuitry  204  may also be known as the “at least one electric circuit” and/or as the “at least one different electric circuit.” 
         [0592]    Continuing discussing  FIG. 25D , in some embodiments, the one or more excitation sources of array-of-excitation-sources  1921  may be proximate (e.g., within a predetermined distance) to material-of-interest  2201 ; such that at least some of the emitted energy from the one or more excitation sources of array-of-excitation-sources  1921  may be received at material-of-interest  2201 , such as at a surface of material-of-interest  2201 . 
         [0593]    Continuing discussing  FIG. 25D , in some embodiments, array-of-excitation-sources  1921  may be attached to, next to, adjacent to, and/or part of complex-impedance-sensor  2010 . 
         [0594]    In some embodiments, a given array-of-excitation-sources  1921 , with the one or more excitation sources, may be incorporated into a given complex-monitoring-sensor-tag  2020  of  FIG. 25A ,  FIG. 25B , and/or  FIG. 25C ; specifically at least attached to (and/or adjacent to) a given complex-impedance-sensor  2010 , in some embodiments. 
         [0595]    In some embodiments, the system for non-invasive monitoring of tissue, may be further characterized as a system for non-invasive detection of problems, conditions, and/or substances of interest within tissue-of-interest (e.g., material-of-interest  2201 ); wherein these problems, conditions, and/or substances may be selected from one or more of: biological cells (e.g., foreign cells, abnormal cells, cancerous cells, etc.), infection, fever, inflammation, antigens, antibodies, foreign substances, tissue conditions, ailments, disease state, and/or the like. Such detection may be a subset of monitoring. 
         [0596]      FIG. 32  may depict a flow diagram illustrating steps in a method  1535   a  for monitoring material-of-interest  2201 . In some embodiments, one or more complex-monitoring-sensor-tag  2020  may be employing electrochemical impedance spectroscopy (EIS). In some embodiments, method  1500  may comprise step  1535   a . In some embodiments, step  1535   a  may follow step  1534 . In some embodiments, step  1535   a  may be a step of the reader  100  (or the reader-and-calibration-member  1109  or the computing device  1807 ) instructing (i.e., commanding and/or requesting) the one more complex-monitoring-sensor-tag  2020 . 
         [0597]    Continuing discussing  FIG. 32 , in some embodiments, method  1535   a  may comprise step  3201 ; wherein step  3201  may be a step of selecting another (or a first) frequency point for which complex impedance may be measured at. In some embodiments, selecting the next frequency point in step  3201  may involve selecting a value of frequency at which a complex impedance of material-of-interest  2201  has not yet been measured. In some embodiments, selecting the next frequency point in step  3201  may involve selecting a value of frequency at which a complex impedance of material-of-interest  2201  has already been measured but under different options; which may include, but may not be limited to, enabling or not enabling excitation sources or enabling different types or combinations of excitation sources among other options. For such different types of excitation sources, see e.g., array-of-excitation-sources  1921  of  FIG. 20B . 
         [0598]    As depicted in  FIG. 19A , real and imaginary parts ∈ r ′ and ∈ r ″, respectively, of complex permittivity ∈ r  may be a function of alternating current (AC) frequency and may be determined at predetermined quantity of frequency values  f =[f 1 , f 2 , . . . , f N ,] where  f  is a vector of N frequencies [f 1 , f 2 , . . . , f N ,], at which real and imaginary parts ∈ r ′ and ∈ r ″, respectively, of complex permittivity  ∈   r  may be determined. 
         [0599]    Using equations (27) and (28) which are copied below for convenience, 
         [0000]    
       
         
           
             
               
                 
                   
                     ɛ 
                     r 
                     ′ 
                   
                   = 
                   
                     Bd 
                     
                       ω 
                        
                       
                           
                       
                        
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                     
                   
                 
               
               
                 
                   ( 
                   27 
                   ) 
                 
               
             
             
               
                 
                   
                     ɛ 
                     r 
                     ″ 
                   
                   = 
                   
                     Gd 
                     
                       ω 
                        
                       
                           
                       
                        
                       A 
                        
                       
                           
                       
                        
                       
                         ɛ 
                         0 
                       
                     
                   
                 
               
               
                 
                   ( 
                   28 
                   ) 
                 
               
             
           
         
       
     
         [0000]    one may express real and imaginary parts ∈ r ′ and ∈ r ″ respectively, of complex permittivity  ∈   r , via real and imaginary components G and B, respectively, of the complex admittance, 
         [0000]    
       
         
           
             Y 
             = 
             
               
                 G 
                 + 
                 jB 
               
               = 
               
                 1 
                 Z 
               
             
           
         
       
     
         [0000]    where Z is the complex impedance. The values of complex impedance Z, from which complex permittivity  ∈   r  may be determined, may be measured at N pre-defined frequencies [f 1 , f 2 , . . . , f N ,]. 
         [0600]    Therefore, in step  3201  another value of frequency from the vector [f 1 , f 2 , . . . , f N ,] may be selected for which complex impedance has not yet been measured (or previously measured, but under different options [conditions]). 
         [0601]    Continuing discussing  FIG. 32 , in some embodiments method  1535   a  may utilize array-of-excitation-sources  1921 , with one or more excitation-sources, as described in the discussion of  FIG. 19F  and in  FIG. 20B . 
         [0602]    Continuing discussing  FIG. 32 , in some embodiments, method  1535   a  may comprise step  3202 . In some embodiments, step  3202  may follow step  3201 . In some embodiments, step  3202  may be a step of determining if the one or more excitation-sources which may be included in the array-of-excitation-sources  1921  are to be enabled. If yes, then method  1535   a  may progress to step  3203 . If no, then method  1535   a  may progress to step  3204 . In some embodiments, criteria for evaluating step  3202  may comprise, but may not be limited to, predetermined settings. 
         [0603]    Continuing discussing  FIG. 32 , in some embodiments, method  1535   a  may comprise step  3203 . In some embodiments, step  3203  may follow a “yes” outcome of step  3202 . In some embodiments, step  3203  may be a step of choosing and enabling one or more excitation-sources which may be included in array-of-excitation-sources  1921 . 
         [0604]    Note, different materials-of-interest (such as different material-of-interest  2201 ) may exhibit different complex impedance or complex permittivity values at the same frequencies when subjected to exposure of external excitation-sources. 
         [0605]    As noted in the discussion of  FIG. 19F  and  FIG. 20B , array-of-excitation-sources  1921  may comprise one or more of: IR light source  1917 , LED light source  1918 , UV light source  1919 , and/or sonic or ultrasonic sound source  1920 . As noted in the discussion of FIG.  23 D, array-of-excitation-sources  1921  may comprise the plurality of IR light sources of type “A”  2318  or/and the plurality of infrared (IR) light sources of type “B”. 
         [0606]    In some embodiments, the plurality of infrared IR light sources of type “A”  2318  and/or the plurality of IR light sources of type “B”  2319  may be of a predetermined frequency (e.g., monochromatic). In some embodiments, the plurality of IR light sources of type “A”  2318  and/or the plurality of IR light sources of type “B”  2319  may be of coherent emission type. 
         [0607]    Continuing discussing  FIG. 32 , in some embodiments, method  1535   a  may comprise step  3204 . In some embodiments, step  3204  may follow a “no” outcome of step  3202 . In some embodiments, step  3203  may be a step of obtain measurement of complex impedance of material-of-interest  2201  when optionally present excitation-sources, such as array-of-excitation-sources  1921  are not activated and/or not enabled, therefore not influencing characteristics of material-of-interest  2201 . 
         [0608]    Continuing discussing  FIG. 32 , in some embodiments, method  1535   a  may comprise step  3205 . In some embodiments, step  3205  may follow step  3204 . In some embodiments, step  3205  may be a step of determining if more measurements of material-of-interest  2201  are required and/or desired (according to predetermined criteria). If yes, then method  1535  may progress back to step  3201 . If no, then method  1535  may progress to completion of method  1535   a.    
         [0609]    In some embodiments, criteria for evaluating step  3205  may comprise, but may not be limited to, enabling or not enabling excitation-sources, using different types or combinations of excitation-sources, performing EIS measurements at different frequency ranges, performing EIS measurements at different values of an alternating current (AC) current source  2106  or different values of an alternating current (AC) voltage source  1906 , among other predetermined options. 
         [0610]    Continuing discussing method  1535   a  of  FIG. 32 , in some embodiments the analysis of the material-of-interest  2201  based on the performed measurements 
         [0611]    may include comparing the obtained measurements of complex impedance or complex permittivity to the previous measurements performed under the same or sufficiently similar conditions such as the choice of type and combination of excitation-sources, frequency range among, other options. Changes in the material-of-interest  2201  that had occurred since the previous measurements may provide a basis for qualitative or quantitative assessment of such changes. 
         [0612]    Continuing discussing method  1535   a  of  FIG. 32 , in some embodiments the analysis of the material-of-interest  2201  based on the performed measurements may include comparing the obtained measurements of complex impedance or complex permittivity to the available reference measurements of the material-of-interest  2201  performed under the same or sufficiently similar conditions such as the choice of type and combination of excitation-sources, frequency range, among other options. 
         [0613]    For example, and without limiting the scope of the present invention, in some embodiments, subjecting the material-of-interest  2201  to excitation-source of predefined characteristic, such as IR light of a certain frequency, may yield a characteristic change in the obtained measurements of complex impedance or complex permittivity as compared to the absence of the said excitation-source. 
         [0614]    In some embodiments, subjecting the material-of-interest  2201  to excitation-source of predefined characteristic, such as IR light of certain frequency may yield a characteristic measurements of complex impedance or complex permittivity as compared to the reference data. 
         [0615]    And such principles are not limited to IR light sources, but may be applied to visible light, UV light, LED light, and/or sound of predetermined characteristics. 
         [0616]    Therefore, some embodiments, of the present invention may be used to detect specific problems, conditions, and/or substances of material-of-interest (e.g.,  2201 ,  1028 , and/or  1828 ), such as, but not limited to, biological cells (e.g., foreign cells, abnormal cells, cancerous cells, etc.), infection, fever, inflammation, antigens, antibodies, foreign substances, tissue conditions, ailments, and/or the like. Detection may be a subset of monitoring. For example, and without limiting the scope of the present invention, by virtue of detecting a characteristic measurement(s) of complex impedance or complex permittivity, with or without excitation source or sources, or by virtue of detecting a characteristic change in the obtained measurements of complex impedance or complex permittivity as compared to the measurements of complex impedance or complex permittivity in the absence of the said excitation-source or sources. 
         [0617]    Some embodiments of the present invention may also be used to detect specific problems, conditions, and/or substances of material-of-interest (e.g.,  2201 ,  1028 , and/or  1828 ), such as, but not limited to, biological cells (e.g., foreign cells, abnormal cells, cancerous cells, etc.), infection, fever, inflammation, antigens, antibodies, foreign substances, tissue conditions, ailments, and/or the like; by virtue of detecting a characteristic change in the obtained measurement(s) of complex impedance or complex permittivity under influence of excitation source or sources as compared to the measurements of complex impedance or complex permittivity when subjected to the excitation-source or sources of a different nature (including but not limited to the frequency of the IR excitation source for example). 
         [0618]    To demonstrate application of the points above, let us assume that the graphs  1911 ,  1912  of  FIG. 19E  correspond to vectors of complex permittivity of the material-of-interest  2201  [∈′ r1 , ∈″ r1 ] measured at a pre-defined frequency range [f 1 ,f 2 ] and obtained without excitation sources. 
         [0619]    Let us assume that the graphs  1913 ,  1914  of  FIG. 19E  correspond to the vectors of complex permittivity of the material-of-interest  2201  [∈′ r2 , ∈″ r2 ] measured at the pre-defined frequency range [f 1 ,f 2 ] and obtained when exposing a given material under test (or under monitoring or under observation) with infrared (IR) light of predetermined frequency. 
         [0620]    Let us assume that the graphs  1915 ,  1916  of  FIG. 19E  correspond to the vectors of complex permittivity of the material-of-interest  2201  [∈′ r3 , ∈″ r3 ] measured at the pre-defined frequency range [f 1 , f 2 ] and obtained when applying IR light of yet another frequency to that same given material-of-interest  2201 . 
         [0621]    The following vectors may be used to identify or detect specific problems, conditions, and/or substances, such as, but not limited to, biological cells (e.g., foreign cells, abnormal cells, cancerous cells, etc.), infection, fever, inflammation, antigens, antibodies, foreign substances, tissue conditions, ailments, and/or the like. The vectors (32), (33), (34), values of which over the frequency range [f 1 ,f 2 ] or its sub-ranges will serve to identify or detect specific problems, conditions, and/or substances: 
         [0000]      [∈ r1 ,∈″ r1 ]  (32)
 
         [0000]      [∈′ r2 ,∈″ r2 ]  (33)
 
         [0000]      [∈′ r3 ,∈″ r3 ]  (34)
 
         [0622]    The vectors (35) and (36), values of which over the frequency range [f 1 ,f 2 ] or its sub-ranges may serve to identify or detect specific problems, conditions, and/or substances. The vectors (35) and (36) may represent the difference in the vectors of complex permittivity of the material-of-interest  2201  introduced by excitation source(s). 
         [0000]      [∈ r2 −∈′ r1 ,∈″ r2 −∈′ r1 ]  (35)
 
         [0000]      [∈′ r3 −∈′ r1 )∈″ r3 −∈′ r1 ]  (36)
 
         [0623]    The vectors (37), (38), and (39) values of which over the frequency range [f 1 ,f 2 ] or its sub-ranges will serve to identify or detect specific problems, conditions, and/or substances. 
         [0000]      [∈′ r1 −∈′ r1   _   ref ,∈″ r1 −∈′ r1   _   ref ]  (37)
 
         [0000]      [∈′ r2 −∈′ r2   _   ref ,∈″ r2 −∈′ r2   _   ref ]  (38)
 
         [0000]      [∈′ r3 −∈′ r3   _   ref ,∈″ r3 −∈′ r3   _   ref ]  (39)
 
         [0000]    where [∈′ r1   _   ref ], [∈″ r1   _   ref ], [∈′ r2   _   ref , ∈″ r2   _   ref ], [∈′ r3   _   ref , ∈″ r3   _   ref ] are reference values of vectors of complex permittivity of the material-of-interest  2201  measured at the pre-defined frequency range [f 1 ,f 2 ] at the same or materially (substantially) similar conditions and under the influence of the same excitation sources as the vectors of complex permittivity of the material-of-interest  2201  [∈′ r1 , ∈″ r1 ], [∈′ r2 , ∈″ r2 ], [∈′ r3 , ∈″ r3 ] respectively. 
         [0624]    The vectors (37), (38), and (39) may represent the measure of closeness of the measured values of vectors of complex permittivity [∈′ r1 , ∈″ r1 ], [∈′ r2 ,∈″ r2 ], [∈′ r3 ,∈″ r3 ] to the reference values of vectors of complex permittivity 
         [0000]    [∈′ r1   _   ref ], [∈″ r1   _   ref ], [∈′ r2   _   ref , ∈″ r2   _   ref ], [∈′ r3   _   ref , ∈″ r3   _   ref ], respectively, of the known specific problems, conditions, and/or substances, under the same excitation sources or the lack thereof. 
         [0625]      FIG. 26  may depict a portion of a material-of-interest  2687 , with a plurality of monitoring-sensor-tags  120 ; wherein the plurality of monitoring-sensor-tags  120  may be on and/or within material-of-interest  2687 . In some embodiments, material-of-interest  2687  may be a structural member, an engineering member, and/or a construction member. For example, and without limiting the scope of the present invention, in some embodiments, material-of-interest  2687  may be a portion of concrete, cement, masonry, and/or the like.  FIG. 26  may also show sections  2688 , which may be sections of material-of-interest  2687 . In some embodiments, a given section  2688  may comprise one or more monitoring-sensor-tags  120  distributed within that given section  2688 . 
         [0626]      FIG. 27A  may depict an imaging-device  2712  for interrogating (reading) at least some of the plurality of monitoring-sensor-tags  120  that may be on and/or within material-of-interest  2687 . In  FIG. 27A , a portion of material-of-interest  2687  may be shown with at least some of the plurality of monitoring-sensor-tags  120 . In some embodiments, imaging-device  2712  may comprise a frame-member  2711  and one or more reader-assemblys  2709 . In some embodiments, the one or more reader-assemblys  2709  may be attached to the frame-member  2711 . In some embodiments, the frame-member  2711  may be a structural member. In some embodiments, each given reader-assembly  2709  may comprise necessary electronics for reading (interrogating) monitoring-sensor-tags  120 . 
         [0627]      FIG. 27B  may show a top view of a given reader-assembly  2709  shown in  FIG. 27A .  FIG. 27C  may be an orthogonal view (e.g., a side view) of the reader-assembly  2709  shown in  FIG. 27B .  FIG. 27B  may show a given reader-assembly  2709  that may be used to image (e.g., read) radiation emitted from at least some of the monitoring-sensor-tags  120 , that may be located on and/or within material-of-interest  2687 . In some embodiments, reference-sensor-tags  1102  may be mounted on reference-housing-member  1107 . In some embodiments, reference-housing-member  1107  may be attached to a portion of frame  2724  of the given reader-assembly  2709 . In some embodiments, readers  100  may be mounted on reader-housing-member  1108 . In some embodiments, reader-housing-member  1108  may be attached to another portion of frame  2724 . In some embodiments, both readers  100  and reference-sensor-tags  1102  may be fixedly mounted on the frame  2724  (e.g., at different locations), and thus may be fixed in position relative to each other. It can be appreciated by one skilled in the art that the locations of reference-sensor-tags  1102  relative to readers  100  are known parameters, or can be mathematically determined, thus allowing a calibration process to increase precision of reading monitoring-sensor-tags  120  associated with material-of-interest  2687 . See e.g.,  FIG. 27B  and  FIG. 27C . 
         [0628]    Continuing discussing  FIG. 27A , in some embodiments, a wheel  2720  of reader-assembly  2709  may facilitate movement of the frame  2724  across a surface of material-of-interest  2687  as portions of this material-of-interest  2687  may be irradiated by readers  100 . In some embodiments, an axle  2722  of wheel  2720  may be in communication with frame  2724 , such that wheel  2720  may rotate about axle  2722  and wheel  2720  may translate with frame  2724 . In some embodiments, frame  2724  may be attached to handle  2726 . In some embodiments, handle  2726  may be telescopic. In some embodiments, handle  2726  may be attached to base  2730 . In some embodiments, base  2730  may be attached to frame-member  2711 . In some embodiments, handle  2726  may be substantially disposed within a hollow portion of a spring  2728 . In some embodiments, wheel  2720  along with handle  2726  (which may be telescopic) with spring  2728  may function to retain reader-assembly  2709  on the surface of material-of-interest  2687 , as the given reader-assembly  2709  (or as image-device  2712 ) translates along the surface of material-of-interest  2687 , obtaining readings from the interrogated monitoring-sensor-tags  120  associated with material-of-interest  2687 . See e.g.,  FIG. 27B  and  FIG. 27C . 
         [0629]    Continuing discussing  FIG. 27B , in some embodiments, structural components of reader-assembly  2709  may comprise at least one of: reference-housing-member  1107 , reader-housing-member  1108 , wheel  2720 , axle  2722 , frame  2724 , handle  2726 , and/or base  2730 . In some embodiments, electronics components of reader-assembly  2709  may comprise at least one of: readers  100 , reference-sensor-tags  1102 , and/or a power source for readers  100 . See e.g.,  FIG. 27B  and  FIG. 27C . 
         [0630]      FIG. 28  may depict a three-dimensional Cartesian coordinate system chosen to determine three-dimensional coordinates of position-reference-tag  1203 , relative to which the positions of readers  100  may be determined. Recall, in some embodiments, readers  100  may be located on each reader-assembly  2709 ; wherein the reader-assemblies  2709  may be components of imaging-device  2712 . And recall, imaging-device  2712  may translate along the surface of material-of-interest  2687 . 
         [0631]    Continuing discussing  FIG. 28 , in some embodiments, coordinates of position-reference-tag  1203  are specified relative to a chosen (e.g., predetermined) Cartesian coordinate system defined by: an origin  2825 , an x-axis  2820 , a y-axis  2821 , and a z-axis  2822 . Locations of reference-sensor-tags  1102  and locations of at least some monitoring-sensor-tags  120  associated with material-of-interest  2687  may be also specified relative to the chosen coordinate system. Recall, in some embodiments, reference-sensor-tags  1102  may be located on each reader-assembly  2709 ; wherein the reader-assemblies  2709  may be components of imaging-device  2712 . 
         [0632]    Also note, any such predetermined Cartesian coordinate system as noted herein may be replaced with other coordinate systems, such as but not limited to, radial, cylindrical, or spherical coordinate systems. 
         [0633]      FIG. 29A  may depict an embodiment of a position-reference-member  2904 . In some embodiments, a given position-reference-member  2904  may be substantially similar to a given position-reference-member  1204 ; except the given position-reference-member  2904  may comprise a transmitter  2926 . In some embodiments, position-reference-member  2904  may be a housing, an enclosure, and/or a structural member. In some embodiments, one or more position-reference-tag  1203  may be mounted or attached to position-reference-member  2904 . In some embodiments, a plurality of position-reference-tag  1203  may be mounted or attached to position-reference-member  2904 . In some embodiments, a relationship between position-reference-tags  1203  and position-reference-member  2904  may be fixed. 
         [0634]    Continuing discussing  FIG. 29A , in some embodiments, transmitter  2926  may be attached to or mounted to position-reference-member  2904 . In some embodiments, transmitter  2926  may communicate wirelessly, using various well known wireless communication protocols, such as, but not limited to, cellular communications, radio-based communications, WiFi, RFID, NFC, magnetic inductive communication, and/or the like. In some embodiments, transmitter  2926  may be in wireless communication with readers  100  of reader-assembly  2709  of imaging-device  2712 . In some embodiments, transmitter  2926  may be in wireless communication with one or more of: devices  1807 , reader-and-calibration-member  1109 , servers  3103 , remote-computing-devices  3105 , WANs  3101  (wide area networks), LANs  3103  (local area networks), and/or the internet  3103 . In some embodiments, remote-computing-devices  3105 , servers  3103 , WANs  3101 , LANs  3101 , and/or the internet  3101  may be remotely located with respect to transmitter  2926 , see e.g.,  FIG. 31 . In some embodiments, transmitter  2926  may be used to wirelessly transmit readings from readers  100 . Such readings could denote and/or convey abnormalities and/or structural problems with material-of-interest  2687 . Inclusion of transmitter  2926  may facilitate automated, automatic, and/or remote monitoring and/or tracking of material-of-interest  2687 . 
         [0635]    In some embodiments, a quantity (predetermined) of reader-and-calibration-member  1109  may be affixed to material-of-interest  2687  (see e.g.,  FIG. 30 ), in order to provide better precision of location information of readers  100  relative to the position-reference-tags  1203  mounted on or attached to position-reference-member  2904 . See e.g.,  FIG. 29A  and  FIG. 30 . 
         [0636]      FIG. 29B  may depict that transmitter  2926  may be connected to a device  1807 , such as a computer. In some embodiments, such a device  1807  may comprise at least processor  1801  and memory  1803 . Note, while position-reference-member  2904  may not be shown in  FIG. 29B , transmitter  2926  may be associated with position-reference-member  2904  as discussed above in the  FIG. 29A  discussion. 
         [0637]      FIG. 30  may be substantially similar to  FIG. 28 , except in  FIG. 30 : (a) one or more reader-and-calibration-member  1109  may be fixedly attached to or mounted to material-of-interest  2687 ; (b) position-reference-member  2904  (e.g., with transmitter  2926 ) may be utilized instead of position-reference-member  1204 ; and/or (c) position-reference-member  2904  may be associated with material-of-interest  2687  instead of a fixed distance from material-of-interest  2687  as shown in  FIG. 28 . As noted above, fixedly attaching or mounting the one or more reader-and-calibration-member  1109  to material-of-interest  2687  may increase precision of various locations measurements (e.g., determining positions of readers  100 , which may then be used to determine positions of monitoring-sensor-tags  120 ). 
         [0638]      FIG. 31  may depict possible remote wireless communications of transmitter  2926 . Remote-computing-device  3105  may be structurally similar to device  1807 , but remotely located with respect to the location of transmitter  2926 . In some embodiments, remote-computing-device  3105  may be selected from: a computer, a personal computer, a desktop computer, a handheld computer, a laptop computer, a tablet computer, a smartphone, a mobile computing device, a computing device, or the like. Note, while position-reference-member  2904  may not be shown in  FIG. 31 , transmitter  2926  may be associated with position-reference-member  2904  as discussed above. 
         [0639]    Note, any of the antennas, receives, transmitters, discussed herein and/or shown in the associated drawing figures, as well as, IR light source  1917 , LED light source  1918 , and/or ultraviolet UV light source  1919 , may emit and/or may receive electromagnetic (EM) radiation (e.g., of a predetermined frequency, including a predetermined ranges of frequency), such as, but not limited to: radio waves, UHF, microwaves, magnetic fields, visible light, UV light, IR light. Note, any of the antennas, receives, transmitters, discussed herein and/or shown in the associated drawing figures, may communicate wirelessly, such as, but not limited to, via: NFC (near field communication), RFID (radio frequency ID) communication, backscatter communication, magnetic induction communication, and/or the like. 
         [0640]    Monitoring-sensor-tags, systems for utilizing such, and methods of use have been described. The foregoing description of the various exemplary embodiments of the invention has been presented for the purposes of illustration and disclosure. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit of the invention. 
         [0641]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.