Patent Publication Number: US-7724139-B2

Title: Universal tracking assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation application of, and claims priority to, U.S. application Ser. No. 12/401,441, filed on Mar. 10, 2009, entitled “UNIVERSAL TRACKING ASSEMBLY”, now abandoned which claims the benefit of U.S. Provisional Application No. 60/871,185, filed Jan. 24, 2007, entitled “UNIVERSAL TRACKING SYSTEM,” U.S. application Ser. No. 12/017,626, filed on Jan. 22, 2008, entitled “UNIVERSAL TRACKING ASSEMBLY”, U.S. Provisional Application No. 61/100,502, filed on Sep. 26, 2008, entitled “MULTIPLE PROTOCOL TRACKING ASSEMBLY” and U.S. Provisional Application No. 61/103,472, filed on Oct. 7, 2008, entitled “UNIVERSAL TRACKING SYSTEM” all of which are hereby incorporated by reference in their entireties. 

   FIELD OF INVENTION 
   The present invention relates, in general, to a universal tracking assembly that is capable of supporting more than one protocol used in electronic article surveillance labels, and deals more particularly with a universal tracking assembly that is capable of responding to both AM and RF interrogation signals. 
   BACKGROUND OF THE INVENTION 
   Bar codes are commonly utilized throughout the commercial and retail worlds in order to accurately determine the nature, cost and other vital data of an individual item. Bar codes, however, are purely passive constructs, and therefore cannot offer or transmit information themselves, instead relying upon known bar code readers to scan and interpret the information stored in the bar code itself. Moreover, the information content of bar codes is static, and cannot be changed or supplemented at will once the bar code is fabricated. 
   In recent years, differing electronic article surveillance (EAS) platforms/tags have been developed to address the shortcomings of known bar code systems. One such type of EAS is radio frequency identification (RFID) platforms/tags. RFIDs are small (typically) battery-less microchips that can be attached to consumer goods, cattle, vehicles and other objects to track their movement. RFID tags are normally passive, but are capable of transmitting data if prompted by a reader. The reader transmits electromagnetic waves that activate the RFID tag. The tag then transmits information via a predetermined radio frequency, or the like. This information is then captured and transmitted to a central database for suitable processing. 
   An RFID system typically is made up of a transponder, or tag, which is an integrated circuit (IC) connected to an antenna, which is then generally embedded into labels, a reader which emits an electromagnetic field from a connected antenna, and an enterprise system. The tag draws power from the reader&#39;s electromagnetic field to power the IC, and broadcasts a modulated signal which the reader picks up (via the antenna), decodes, and converts into digital information that the enterprise system uses. 
   There are two main types of RFID devices, including inductively coupled RFID tags, which may be UHF as are the current Gen 2 tags. Typically, there are three main parts to an inductively coupled RFID tag:
         Silicon microprocessor—These chips vary in size depending on their purpose;   Metal coil—Made of copper or aluminum wire that is wound into a circular pattern on the transponder, this coil acts as the tag&#39;s antenna. The tag transmits signals to the reader, with read distance determined by the size of the coil antenna. These coil antennas can operate at many frequencies, including the UHF Gen 2 tag frequency which is currently specified as approximately 920 MHz; and   Encapsulating material—glass or polymer material that wraps around the chip and coil.       

   Inductive RFID tags are powered by the magnetic field generated by the reader. The tag&#39;s antenna picks up the magnetic energy, and the tag communicates with the reader. The tag then modulates the magnetic field in order to retrieve and transmit data back to the reader. Data is transmitted back to the reader, which directs it to the host computer and/or system. 
   Inductive RFID tags are very expensive on a per-unit basis, costing anywhere from $1 for passive button tags to $200 for battery-powered, read-write tags. The high cost for these tags is due to the silicon, the coil antenna and the process that is needed to wind the coil around the surface of the tag. 
   Another type of known RFID are capacitively coupled RFID tags. These tags do away with the metal coil and use a small amount of silicon to perform that same function as an inductively coupled tag. A capacitively coupled RFID tag also has three major parts:
         Silicon microprocessor—Motorola&#39;s BiStatix RFID tags use a silicon chip that is only 3 mm 2 . These tags can store 96 bits of information or more, which would allow for trillions of unique numbers that can be assigned to products;   Conductive carbon ink—This special ink acts as the tag&#39;s antenna. It is applied to the paper substrate through conventional printing means; and   Paper—The silicon chip is attached to printed carbon-ink electrodes on the back of a paper label, creating a low-cost, disposable tag that can be integrated on conventional product labels.       

   By using conductive ink instead of metal coils, the price of capacitively coupled tags are fractions of a dollar. These tags are also more flexible than the inductively coupled tag. Capacitively coupled tags can be bent, torn or crumpled, and can still relay data to the tag reader. In contrast to the magnetic energy that powers the inductively coupled tag, capacitively coupled tags are powered by electric fields generated by the reader. The disadvantage to this kind of tag is that it has a very limited range. 
   While the retail industry recently settled on using UHF Gen 2 passive RFID for item level tags as a minimum, as the two preceding examples of known RFID devices indicates, there does not presently exist a generalized industry-standard RFID protocol. With different manufacturers utilizing different RFID devices on their disparate products, large department stores, warehouses and/or shipping containers often contain a plurality of differing RFID devices. 
   Still further, known RFID devices are designed so that they may continue to communicate with extraneous readers well after the time of initial purchase. That is, known RFID devices are designed so that tracking of an item can be accomplished from the time the item leaves the factory, until it rest within the residential dwelling of its purchaser. 
   The very attributes, however, of known RFID devices that permit these devices to continue to operate and communicate with a reader well after the time of initial purchase, also poses problems for closely nested commercial or retail facilities. 
   For example, once a purchaser buys an item at a store, the RFID device will communicate with an integrated reader at the checkout. The reader will detect and interrogate the RFID device, and thereafter permit the purchaser to exit the store without setting of an alarm for shoplifting. But because of the resilient nature of the RFID devices, these devices continue to be passively ‘active’ even if the purchaser goes into another retail establishment, as often happens in a mall or shopping center environment. Once the original purchaser leaves the second retail store, the RFID detection equipment in the second store may awaken the RFID tag, and erroneously alert the security system of the second store. This scenario is only worsened by the differing RFID devices and protocols that potentially can exist in the market. 
   In addition to the differing RFID technologies mentioned above, other EAS technologies exist having their own operational protocols, such as acousto-magnetic (AM) EAS circuitry. Similar to the problems noted above, the problem for, e.g., manufacturer is the uncertainty of knowing which EAS technology will be employed at various stages of the manufacture, transportation and inventory of items equipped with one of the many differing EAS technologies. 
   It will therefore be appreciated that the primary EAS protocols in place are the acousto-magnetic (AM) type and the RF type, as discussed above. These differing EAS protocols are each independently used by various major retailers and are currently not compatible technologies. Thus, a manufacturer/distributor must maintain separate inventories of their products for the different EAS protocols incurring the added cost in doing such a practice or the manufacturer/distributor must apply both tags/labels to each of their products incurring the added cost of this alternative practice. 
   With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a universal tracking system that is capable of harmonizing the use of differing EAS technologies/devices by integrating more than one such technology on a common substrate/platform. More preferably, it is the general object of the present invention to provide an integrated EAS label/tag assembly, which is compatible with both AM type and RF (including RFID) systems. The invention more preferably includes the AM type transponder which is composed of one or more amorphous alloy strips with a high magnetic permeability and a magnetic biasing strip which can be cast, die cut, painted, printed, etc. The amorphous strip(s) are packaged such that they can freely resonate and is (are) sized to resonate at the desired frequency of standard AM type EAS. 
   SUMMARY OF THE INVENTION 
   It is one object of the present invention is to provide a universal tracking assembly. 
   It is another object of the present invention is to provide a universal tracking assembly that is capable responding to more than one EAS interrogation protocols. 
   It is another object of the present invention is to provide a universal tracking assembly that integrates differing EAS identification technologies upon a common platform. 
   It is another object of the present invention is to provide a universal tracking system that integrates both RF and AM EAS identification technologies upon a common platform. 
   It is yet another object of the present invention to provide a combined electronic article surveillance (EAS) tag/label assembly which is capable of being detected by, and of responding to, interrogation by either AM or RF technologies/protocols. 
   It is yet another object of the present invention to provide a combined electronic article surveillance (EAS) tag/label which is capable of utilizing at least one common element in support of the combined AM and RF technologies/protocols. 
   It is yet another important aspect of the present invention to provide a combined EAS tag/label wherein the biasing magnet of the AM circuitry is integrated into both the AM and RF circuitry, thereby affecting the capacitance and/or inductance of the combined EAS tag/label. 
   It is yet another important aspect of the present invention to provide a combined EAS tag/label wherein the biasing magnet of the AM circuitry is positioned adjacent the inductive coil of the RF circuitry, thereby affecting the capacitance and associated inductance of the combined EAS tag/label. 
   Thus, it is an object of the present invention is to make a hybrid (i.e., combined) and selectively deactivatable EAS tag/label that can be detected by both AM EAS detectors and RF EAS detectors (also including RFID). The manufacture/design of this hybrid EAS tag/label is such that the intrinsic properties of the components enhance the performance of the overall hybrid label/tag and that the manufacturing efficiencies allow for a less expensive EAS solution for the manufacturer/distributor. 
   These and other objectives of the present invention, and their preferred embodiments, shall become clear by consideration of the specification, claims and drawings taken as a whole. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  schematically illustrates a known RFID EAS assembly. 
       FIG. 2  schematically illustrates another known RFID EAS assembly. 
       FIG. 3  schematically illustrates another known RFID EAS assembly. 
       FIG. 4  schematically illustrates another known RFID EAS assembly. 
       FIG. 5  schematically illustrates an integrated RFID EAS assembly according to one embodiment of the present invention. 
       FIG. 6  schematically illustrates an integrated RFID EAS assembly according to another embodiment of the present invention. 
       FIG. 7  illustrates a flow diagram pertaining to the integrated RFID EAS assembly of  FIG. 6 . 
       FIG. 8  illustrates a top plan view of a combined EAS tag/label assembly exhibiting integrated AM and RF components, according to a preferred embodiment of the present invention. 
       FIG. 9  illustrates a side view of the combined EAS tag/label assembly shown in  FIG. 8 . 
       FIG. 10  illustrates a flow diagram showing the selective activation/deactivation of either the AM or RF portions of the combined EAS tag/label assembly shown in  FIGS. 8-9 . 
       FIG. 11  illustrates a schematic view of a universal tracking assembly in accordance with an alternative embodiment of the present invention. 
       FIG. 12  illustrates a side view of the universal tracking assembly of  FIG. 11 . 
       FIG. 13  illustrates a graph depicting a Q value associated with the universal tracking assembly of  FIG. 11 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Known EAS assemblies, such as RFID tags, can be either active or passive. Active RFID tags include a battery, or the like, and so are capable of transmitting strong response signals even in regions where the interrogating radio frequency field is weak. Thus, an active RFID tag can be detected and transmit at a greater range than is possible with a passive RFID. Batteries, however, are limited in their operable lifetime, and add significantly to the size and cost of the tag. A passive tag derives the energy needed to power the tag from the interrogating radio frequency field, and uses that energy to transmit response codes by modulating the impedance the antenna presents to the interrogating field, thereby modulating the signal reflected back to the reader antenna. Thus, their range is more limited. 
   Even within known passive RFID tags, there exists significant differences in performance, including significant differences in the performance of their associated antennas and corresponding interrogation and response ranges. While one embodiment of the present invention will be hereafter described in connection with passive tags, it will be readily appreciated that the teachings of the present invention are equally applicable to active tags. 
     FIG. 1  illustrates one version of a passive RFID  10 , which typically includes an integrated circuit  12  and an antenna  14 . The integrated circuit  12  provides the primary identification function. It includes software and circuitry to permanently (or semipermanently) store the tag identification and other desirable information, interpret and process commands received from the interrogation hardware, respond to requests for information by the interrogator, and assist the hardware in resolving conflicts resulting from multiple tags responding to interrogation simultaneously. Optionally, the integrated circuit may provide for updating the information stored in its memory (read/write) as opposed to just reading the information out (read only). 
   The antenna geometry and properties depend on the desired operating frequency of the RFID portion of the tag. For example, 2.45 GHz (or similar) RFID tags would typically include a dipole antenna, such as the linear dipole antennas  4   a  shown in  FIG. 1 , or the folded dipole antennas  14   a  shown attached to the passive RFID  10   a  in  FIG. 2 . A 13.56 MHz (or similar) RFID tag would use a spiral or coil antenna  14   b , as shown in the RFID  10   b  of  FIG. 3 . Other frequencies of RFID are accomplished with similar antenna geometries. 
   Regardless of the particular design, the antenna  14  intercepts the radio frequency energy radiated by an interrogation source. This signal energy carries both power and commands to the tag. The antenna enables the RF-responsive element to absorb energy sufficient to power the IC chip and thereby provide the response to be detected. Thus, the characteristics of the antenna must be matched to the system in which it is incorporated. In the case of tags operating in the high MHz to GHz range, the most important characteristic is the antenna length. Typically, the effective length of a dipole antenna is selected so that it is close to a half wavelength or multiple half wavelength of the interrogation signal. In the case of tags operating in the low to mid MHz region (13.56 MHz, for example) where a half wavelength antenna is impractical due to size limitations, the important characteristics are antenna inductance and the number of turns on the antenna coil. For both antenna types, good electrical conductivity is required. Typically, metals such as copper or aluminum would be used, but other conductors, including magnetic metals such as permalloy, are also acceptable. 
     FIG. 4  illustrates a passive RFID tag  10   c  which utilizes a conductive ink portion  14   c  to act as the antenna for the RFID  10   c . Although less expensive to fabricate than RFID tags that include a wound wire antenna array, the conductive ink antenna  14   c  is limited in range and power. 
   In sum, therefore, there exists several differing types of RFID tags, which can either incorporate a magnetically responsive element, or a RF responsive element. As will be understood, each of these differing types of tags require differing interrogation devices and protocols so as to effectively interact with each tag type. This situation is difficult for large retailers, or the like, who inevitably accept product from a vast array of manufacturers utilizing differing RFID tag types. 
     FIG. 5  illustrates, therefore, one embodiment of the present invention. As shown in  FIG. 5 , a single, integrated RFID tag  20  includes both a magnetically-responsive RFID  22  and an RF-responsive RFID  24 . When so coupled on a single RFID tag, these two RFID tag-types ensure that whatever type of interrogation device is employed by a user or, e.g., a retail store, the system will be able to communicate with at least one of the tags  22 / 24 . 
   It is therefore an important aspect of the present invention that more than one type of RFID tag be integrated into a single RFID tag. By doing so the present invention ensures that regardless of the interrogation system utilized at or in any particular location, at least one of the integrated RFID tags will respond to the interrogation with the required information. Thus, a retail store need only buy a single interrogation system, without fear of not being able to communicate with those items having RFID tags of differing types. 
   It will be readily appreciated that the present invention is not limited to the integration of magnetically-responsive RFIDs and RF-responsive RFIDs together, and extends to the integration of RFID tags of any known, or to be discovered, type. 
   It is a further object of the present invention that significant elements present in one RFID tag may be universally utilized with respect to the other integrated RFID tags present on the integrated RFID tag  20 . For example, should the integrated RFID tag  20  support both the RFID tags of  FIGS. 3 and 4 , the RFID tag of  FIG. 4  could utilize the antenna  14   b  of the RFID tag in  FIG. 3 , thereby increasing the range of the conducive-ink RFID tag illustrated in  FIG. 4 . 
   It will be readily appreciated that the common use of a single component between differing RFID tags is not limited to the sharing of an antenna element. Indeed, the present invention equally contemplates the shared use of any component found in any RFID tag that are jointly mounted on a unitary platform. 
     FIG. 5  illustrates the shared use of a battery, or power supplying element,  26  with both of the RFIDs  22 / 24 . The use of a shared or common power source  26  effectively removes the range limitations associated with certain types of RFID tags, as well as being more economically practical than providing a separate power source for each of the integrated RFIDs. 
   As discussed previously, large retailers, or the like, often accept merchandise from a variety of manufacturers who may be located at disparate points around the world. Each of these individual manufacturers may place an RFID tag of their choosing on the item as it is produced. This item is then transported by a shipper who may also place another RFID tag on the item, in accordance with the particular RFID system/configuration the shipper utilizes. Finally, the retailer itself may place yet another RFID tag on the item, again of its own choosing and configuration, and one which operates well with the interrogation system employed by the retailer. 
   In sum, any given item may have a plurality of differing RFID tags located, glued or otherwise attached thereto. Thus, while the retailer may deactivate their RFID tag placed on the item as the customer leaves the store, a problem exists when the retailer&#39;s deactivation system does not communicate with the other types of RFID tags that may also be located in or on the item. 
   When one or more of the additional RFID tags on a given item are not suitably deactivated, owing to their differing configurations and protocols, it is possible that the consumer may walk into another, non-affiliated store with the first item purchased, only to have the non-deactivated RFIDs set off the security system of the second store. 
   The integrated nature of the RFID tag  20  shown in  FIG. 5  removes the possibility of any such erroneous indications of shoplifting, or the like, caused by the non-deactivated RFID tags.  FIG. 6  illustrates an integrated RFID tag  30 , supporting an array of six differing RFID tags  32 . It will be readily appreciated that there be more or less RFID tags  32  formed on the integrated RFID tag  30 , without departing from the broader aspects of the present invention. 
     FIG. 7  is a flow diagram illustrating the operation of the integrated RFID tag  30  shown in  FIG. 6 . As depicted in step  34 , an interrogator (such as one of the known RFID readers) is utilized to scan or interrogate the RFID tag  32 . The interrogator then identifies one or more RFID tags  32  present in the array which are compatible with the technology of the interrogator, in step  36 . The interrogator will then issue a command or signal to deactivate those RFID tags in the array which are compatible with the interrogator, as depicted in step  38 . Following this, in step  40 , the deactivation signal is communicated internally of the RFID tag  30 , to the non-deactivated RFID tags  32 , thereby deactivating all of the RFID tags  32 , regardless of their configuration or protocol. 
   It is therefore another important aspect of the present invention that the integrated nature of the RFID tag  30  enables the complete deactivation of all of the RFID tags  32  anytime when the interrogator is capable of deactivating even one of the RFID tags  32  in the array. Thus, once a consumer purchases an item, and the interrogation system employed by the retail store deactivates the store RFID, the present invention ensures that all other RFIDs (or other types of EAS assemblies, as discussed in more detail later) in the array will also be deactivated. Erroneous indication of shoplifting or the like, as the consumer moves from store to store with a previously purchased item, are thereby avoided. 
   The communication between the RFID tags  32  may be accomplished through a direct electrical connection, or filament,  44  (as shown in  FIG. 6 ), or via electromagnetic coupling, such as parasitic coupling, capacitive coupling or inductive coupling. 
   When employing the combined (or, integrated) RFID tag  30  in accordance with the present invention, none of the existing industries or retail stores need change the protocol by which they interrogate their combined RFID tags, regardless of the technology underpinning each of the differing RFID circuitry supported thereon. That is, regardless of the interrogation or reader apparatuses utilized by the various manufacturing and retail outlets, an integrated and combined EAS tag assembly will always have at least one type of RF circuitry that is capable of communicating with the respective interrogator or reader. 
   Given the differing technologies currently utilized by various manufacturers of RFID EAS tags, and the anticipated continuing evolution of technology in this area, the integrated RFID tag of the present invention effectively mimics a universal standard of RFID technology and related interrogators/readers, which does not currently exist. Thus, until such a standard is accepted worldwide, the integrated RFID tag of the present invention provides a platform upon which to mask the differences between the competing RFID technologies. 
   Other embodiments of the present invention can be visualized by a review of the foregoing. As to the integrated RFID tag  20  shown in  FIG. 5 , the present invention equally contemplates that the deactivation signal communicated to either the RFID  22  or  24  is likewise communicated to the common power source  26 . By changing the state of the power source, the deactivation of the RFID  22  will effectively also deactivate the RFID  24 . 
     FIGS. 5-7  therefore exhibit related embodiments of a combined EAS assembly having a plurality of RFID technologies integrated thereon. Thus, the combined EAS assemblies shown in  FIGS. 5-7  are capable of responding to interrogation by differing RFID protocols. 
   In yet another, preferred, embodiment of the present invention, a combined EAS assembly  50  is shown in  FIGS. 8-9 . As shown in  FIGS. 8-9 , the combined EAS assembly  50  integrates both AM and RF components and technologies in a single, combined and universal EAS tag/label assembly. 
   The combined EAS tag assembly  50  includes a first portion  52  of a RF component which exhibits inductance, a second portion  54  of a RF component which exhibits capacitance, a third multi-layer portion  56  of an AM component including a resonator and a bias magnet, and a fourth portion  58  acting as the substrate and backing of the combined EAS tag  50 . As shown in  FIG. 9 , the third multi-layer portion  56  includes an amorphous resonator  60  and a bias magnet  62 . 
   Known RF resonators are typically configured as a LC Tank circuit, typically consisting of simply an inductor and capacitor(s). In contrast, the EAS tag assembly  50  will capture the resonant frequency of both the RF and AM components of the label and allow for a space in the center of the RF circuit to place the AM type label. The AM portion can be placed at various locations on the RF circuit, but interactions have to be accounted for and the RF portion must be tuned. Placing the AM components in the center of an open space in a RF circuit will primarily effect the inductance. Placing the AM portion in other locations could effect inductance, depending on the means of attaching or the dielectric, and certainly capacitance. Either way, once the AM portion is positioned in an inactive state, the RF portion is designed around the AM components and tuned to accommodate the interaction for any capacitance or inductance effects. This tuning will account for center frequency and the quality of the circuit. 
   The RF label components can be produced by various manufacturing methods such as die cutting, laser cutting, hot foil printing, embossing, printing with conductive inks, etc. . . . . The method of manufacture is secondary in importance to the design of the RF portion of the combined EAS tag assembly  50 . The means and location of the AM circuitry portion in relation to the RF circuitry portion will affect the advantage of shielding properties. The RF label component in accordance with the embodiment shown in  FIGS. 8-9  can therefore be generally formed or stamped out of a material and forming the LC tank circuit which resonates at the desired frequency. The LC tank circuitry may itself be formed by layering “foils” (or inks, etc.) with designed dielectrics to form the inductor and plate capacitors. 
   It is therefore another important aspect of the present invention that the RF subsystem of the EAS tag assembly/label  50  is formed in a way and with specific materials that the combined EAS tag/label assembly  50  resonates at the appropriate frequency as an AM label would. 
   Similar to known AM labels, the subsystem of the EAS tag assembly  50  will continue to include the bias magnet  62 , one or more resonators  60  cut from an amorphous alloy such as MetGlas (Metglas 2826MB3 has been used, however it will be readily appreciated that the present invention is not limited by this particular alloy), and packaging to allow for magnetorestriction and resonance. 
   It is therefore another important aspect of the present invention that the design of the EAS tag assembly  50  allows for at least one of these AM circuit components to be part of the RF circuit. The balance/tuning of the AM subsystem is effected at least in part by the inclusion of additional resonators and shaping of the primary to not only accomplish the RF subsystem, but contribute to the resonance of the AM subsystem. These AM label components may also be produced by a variety of manufacturing methods and may include die cutting, printing the bias magnet, etc. It will be readily appreciated that the specific method of manufacture either the RF or AM components of the EAS tag assembly  50  is secondary to the design of the combined EAS tag assembly  50 , and that the present invention is not limited by the manner in which the EAS tag assembly is manufactured. 
   Yet, another important aspect of the present invention is that the design of the EAS tag assembly  50  will allow for only one portion to be active at a given time. Thus, when the tag is activated for AM, it is deactivated for RF. This is coincident with the intrinsic properties of the labels themselves, as expressed: 
   
     
       
         
             
             
             
           
             
                 
                 
             
             
                 
               AM 
               RF 
             
             
                 
                 
             
           
          
             
                 
             
          
         
         
             
             
             
             
          
             
                 
               Activation 
               Magnetize 
               De-magnetize 
             
             
                 
               De-Activation 
               De-magnetize 
               Magnetize/RF 
             
             
                 
                 
                 
               Shorting 
             
             
                 
                 
             
          
         
       
     
   
   Thus, in a preferred embodiment, the resonator component (which may be formed from Metglas or from many of the known amorphous alloys, used for the magnetorestrictive resonator) will be employed as not only the resonator in the AM subsystem, but may be a layer or a portion of a layer of the RF subsystem. The bias magnet  62  may also be a layer or a portion of a layer. 
   Moreover, the resonator component can also be effective for EMF shielding. As such, when a shield is placed behind the RF component, the signal from the RF is not absorbed by the package that it is trying to protect, but is directed outward toward the EAS gate which is meant to detect the signal. The shielding aspect can coexist with the actual performance of both the AM and the RF components when the RF circuit is designed and tuned to accommodate the interaction between the two. However, as stated previously, the means and location of the AM portion in relation to the RF portion will effect the advantage of shielding properties. 
   It will therefore be readily appreciated that with the combined EAS tag assembly  50 , a manufacturer can incorporate the label/tag  50  into a product or packaging during manufacture and maintain a single inventory. When the order for a product comes in, the products are picked and then the appropriate AM or RF component is activated/deactivated. This can be done automatically on a conveyor system or individually. A flow chart depicting the simplicity of this is shown in  FIG. 10 . 
   Thus, a preferred embodiment of the present invention provides an integrated EAS label/tag assembly  50  which is compatible with both AM type and RF (including RFID) systems. The invention includes the AM type transponder which is composed of one or more amorphous alloys strips with a high magnetic permeability and a magnetic biasing strip which can be cast, die cut, painted, printed, etc. . . . . The amorphous strip(s) are packaged such that they can freely resonate and is (are) sized to resonate at the desired frequency of standard AM type EAS. 
   The invention also includes the RF (or RFID) component which can be manufactured by any number of know processes. The process of die cutting or laser cutting the material is the preferred method (however, any number of methods may be used), since it minimizes the steps of manufacture, amount of equipment and eases the capability of mass producing a fine tuned RF type EAS tag. 
   Moreover, The RF subsystem of the combined EAS tag/label assembly  50  is characterized as a LC Tank Circuit where the angular frequency is equal to: 
           ω   =       F   ang     =       1   LC               
in radians/sec; where L is in Henries and C is in Farads;
 
Resonant Frequency is equal to:
 
           ω   =       F   res     =       1   LC               
in radians/sec; where L is in Henries and C is in Farads;
 
   Measured in Hertz 
   
     
       
         
           F 
           = 
           
             
               ω 
               
                 2 
                 * 
                 π 
               
             
             = 
             
               1 
               
                 2 
                 * 
                 π 
                 * 
                 
                   LC 
                 
               
             
           
         
       
     
   
   The AM subsystem of the combined EAS tag/label assembly  50  is characterized by one or more strips or ribbons of an amorphous magnetorestrictive alloy, which is magnetically biased by the placement of the bias magnet. The resonator(s) provide consistent resonant frequency when a given bias field is applied. Although it is common to have multiple resonators, the design of the present invention does not preclude the use of a single resonator or multiple arrangement. In simplistic terms, resonators of the same thickness can be accomplished as long as the length is constant and total width is approximately the same. For approximation, if a single resonator can be designed with a length of approximately 38 mm and a width of 2x, two individual resonators of the same length can be used with a width of x, assuming consistent thickness. 
   The combined RF (including RFID) and AM label/tag provides the overall system with not only a less expensive means of manufacturing these labels/tags independently, but provides a potential improvement in performance and product shielding. Depending upon the position of the AM portion in relation to the RF portion, shielding may be improved. The resonators, being an amorphous alloy, are intrinsic shielding materials. Customized designs following this method allow that the RF signature will not be absorbed by the product being labeled, since the amorphous alloys used as resonators in the AM tag will shield the product and reflect the signal outward in the desired direction. 
   It is therefore an important aspect of the present invention that the combined EAS tags described in connection with the embodiments of  FIGS. 5-10  each contain at least a first and a second circuit portions, each of which are capable of excitation (or ‘interrogation’, by a suitable reader/writer) by separate technological protocols. Thus, a combined EAS tag/label assembly is created which may properly communicate with any number of differing interrogation protocols, regardless of the technology protocol of the interrogator/reader. 
   It will also be appreciated that the disclosed embodiments as presented in connection with  FIGS. 5-10  are not limiting in the nature of the EAS circuitry integrated in the combined EAS tag/label. That is, any number or differing types of EAS circuitry, in existence now or developed in the future, may be integrated onto a common substrate of an EAS tag/label, without departing from the broader aspects of the present invention. Moreover, although the present invention envisions integrating differing types of EAS circuitry onto a common substrate, each being capable of excitation/interrogation by the appropriate interrogation protocols, the combined EAS tag/label of the present invention seeks to utilize at least one common element, or component, between the differing EAS circuitry. In this manner, a reduction in the overall size and cost of the combined EAS tag/label assembly of the present invention is realized. 
   Referring now to  FIGS. 11-13 , an alternative embodiment of the inventive tracking assembly is disclosed. More specifically, the depicted embodiment is an EAS tracking tag/label that includes both an RF circuit and an AM circuit in a single, stacked hybrid assembly. The stacked configuration of the hybrid RF/AM assembly is facilitated through the use of a bias magnet as a shared component between the RF and AM circuits. 
   As shown in  FIGS. 11 and 12 , the inventive tag  100  includes a substrate  110 . As will be appreciated, the substrate  110  may be manufactured from a variety of materials including paper and the like. The substrate  110  has an adhesive layer  120  ( FIG. 12 ), which secures the hybrid RF/AM circuit to the substrate  110 . The substrate  110  may also have an attachment surface or backing  115  with a peel-off layer allowing the substrate  110  to be secured to a package. 
   Affixed to the substrate  110  is a coil inductor  130  of the RF circuit, which as discussed above, is an LF tank circuit. As shown, a portion of the coil inductor  130  is overlapped by another section of foil or magnetic ink, thereby forming a plate capacitor  140 . As mentioned, the capacitor  140  is preferably a second layer of foil that has been secured to the inductor  130  with dielectric glue. The capacitor  140  also has a plurality of cut-away portions  180  which can be broken or blown out with high-energy RF to disable the RF portion of the inventive tag should the tag be for use with AM readers exclusively. 
   The coil inductor  130  may itself be manufactured from a foil or a metallic ink. Preferably, the coil inductor  130  is foil and is manufactured using a die cut process in which the inductor  130  and capacitor  140  are cut from a single piece of foil. When cut from a single piece of foil, the die cut foil would include a fold line allowing the ‘capacitor’ portion  140  to be folded over the ‘inductor’ portion  130 , and glued in place. The size of the inductor  130  may vary provided that it has a width large enough to accommodate the bias magnet and the resonator strips of the AM circuit, as will be discussed in more detail below. 
   Referring again to  FIGS. 11 and 12 , the coil inductor  130  has a layer of dielectric material  145  separating it from a bias magnet  150 . The bias magnet  150  is preferably a unitary single piece magnet and, as is known, is typically employed in AM-type EAS tags. While a single-piece magnet has been described, the present invention is not so limited in this regard, as the magnet may alternatively be formed as a multi-piece structure, without departing from the broader aspects of the present invention. Indeed, a primary concern is that the magnetic component evidence two spaced apart poles, regardless of the specific structure of the bias magnet  150 . Moreover, and with respect to employing spaced apart poles, the poles being located on a portion of the inductor and capacitor, a substantial cost savings may be realized over the use of a single piece bias magnet, as less magnetic material would obviously be required. 
   In its preferred configuration, however, the bias magnet  150  is a single unitary 38 mm×4 mm Arnochrome permanent magnet that is situated so that it overlaps, in superposition, both a portion of the inductor  130  and plate capacitor  140  on top of the inductor  130 . Importantly, in this location, the bias magnet  150  increases the capacitance of the RF circuit and becomes, in essence, part of the capacitor  140 . Indeed, the area of overlap between the plate capacitor  140  and inductor  130  can be reduced or expanded in accordance with the size of the bias magnet  150  to achieve a desired resonance frequency. 
   As will be appreciated, the bias magnet  150  is a preferred shared component between the RF circuit and the AM circuit in the inventive hybrid assembly of the present embodiment. The AM portion of the assembly includes the bias magnet  150  and multiple resonator strips  170  located within an insulative bubble-type enclosure or pack  160 , preferably manufactured from plastic. The resonator strips  170  may be formed from Metglas or from many known amorphous alloys. The bubble pack  160  is insulative so that the resonator strips do not affect the capacitance of the RF circuit. Preferably, the bubble pack  160  is secured to the bias magnet  150  by gluing the edges of the pack  160  directly to the bias magnet  150 . 
   The use of the bias magnet  150  in the RF circuit is an important aspect of the present invention. The bias magnet  150  effectively increases the capacitance of the RF circuit, while also allowing the AM portion to be stacked directly on top of the RF portion without destroying the functioning of either the AM or RF portions of the universal tracking tag/assembly  100 . 
   Indeed, simply mounting an AM circuit and RF circuit, in close association on the same tag substrate, serves to interfere with the capacitance of the RF circuit, e.g., thereby reducing the resonance frequency from the (e.g.) required 8.2 MHz, and potentially rendering both circuits unsuitable for use. 
   In sharp contrast, the present invention has determined that by employing the bias magnet  150  (a necessary component of known AM circuitry) in a superpositional orientation over the existing coil inductor of the RF circuitry, the bias magnet  150  actually performs a dual function without harming the operational characteristics of either the AM or RF portions of the universal tag/assembly  100 . Thus, an important aspect of the present invention lies in utilizing the biasing magnet  150  of known AM circuitry to act also as a capacitive element for a RF EAS tag, by locating the bias magnet  150  in superposition over at least a portion of the coil inductor of the RF circuitry. 
   In addition to the concept of integrating the bias magnet  150  in the manner discussed above, it is yet another important aspect of the present invention that the length of the bias magnet may itself be varied in order to alter the total capacitance of the RF circuit, i.e., in order to ‘tune’ the circuit. This eliminates the need to alter the amount of overlap between the foil capacitor and the induction coil, which is more difficult to vary upon manufacture than is the length of the baising magnet, which is a separate component placed on top of and affixed to the previously manufactured and assembled substrate, inductor and capacitor. 
   Additionally, the present invention also contemplates that it is possible to simply change the position of the bias magnet  150 , relative to the capacitor and inductor portions of the universal tag/assembly  100 , so that only a predetermined portion of the bias magnet overlaps these components to alter the capacitance of the RF circuit. For the above reasons, the inventive tag provides an ease of manufacture, and a degree of versatility, previously unknown in the art. 
   The ability to easily tune the inventive EAS tag/assembly  100  is important, particularly in situations where the specific packaging of a commodity is known to bring an RF tag out of tune. For example, with tobacco products such as cigarettes, the packaging typically includes a foil paper lining. This foil lining affects the capacitance of an RF circuit effectively throwing an RF EAS tag out of tune and rendering it ineffective for its intended purpose. Therefore, separate RF tags are typically manufactured specifically for such packaging, and the resultant customization of such packaging obviously increases the cost of manufacture, as well as increasing the complexity of selecting the proper RF EAS circuitry for the specific commodity being shipped. 
   Thus, it is yet another important aspect of the present invention that the length of the bias magnet can be selectively altered, thereby changing the capacitance of the RF circuit to take into account the foil lining of the packaging such that the tag  100 , when placed on such packaging, provides the proper resonance frequency of 8.2 MHz. This relatively simple modification does away with the need to manufacture a plurality wholly separate tags, for use with a matching plurality of differing commodities that each have their own ‘capacitance profile’, due to foil packaging or the like. 
   As stated, the hybrid inventive circuit/assembly  100  may be tuned by selectively varying the length of the bias magnet  150 . Typically, both RF and AM circuits are tuned, e.g., the capacitance and inductance are modified, to result in a maximized “Q” value ( FIG. 13 ). The Q is a measure of quality of the resonant frequency of a circuit.  FIG. 13  graphically depicts an idealized Q value with a high peak to peak (P-P) value  200  over a relatively narrow frequency range. Varying the length or overlap of the bias magnet can tune the hybrid AM/RF circuit until optimal Q values are obtained for both the RF and AM portions of the circuit. 
   Turning back to the stacked configuration of the hybrid RF/AM circuit it will be appreciated that this configuration is a significant feature of the present invention. There are literally millions of EAS tags deployed by manufacturers, distributors and retailers for inventory tracking and control. Given the high volume of tags, cost savings, ease of manufacture and universal adaptability are of particular importance. With these goals in mind, the stacked hybrid assembly with its shared bias magnet allows for the creation of a single tag with both RF and AM circuits. 
   In particular, the inventive hybrid assembly  100  of the present invention provides for a significant savings as it eliminates the need for separate RF and AM tags. For example, where the type of EAS reader/interrogator varies from location to location during shipment and sale of goods, it is known to place two wholly separate tags on a package, e.g., one for an RF reader and another for an AM reader. As will be apparent, the deployment of separate tags requires the manufacture and deployment of separate tags. The present invention reduces these costs through the use of a single tag with a hybrid AM/RF circuit. 
   In addition to reducing costs, the use of a single tag with the inventive hybrid circuit provides a level of adaptability and convenience not available with known EAS tags. Indeed, the hybrid tag, and any accompanying packaging, may be shipped with only the RF circuit activated, the AM circuit activated or both the AM and RF circuits activated. This is important in that it allows a single tag to be configured for multiple applications. That is, the RF circuit, for example, may be permanently disabled with a burst of high-energy RF signal where it is known that the tag will be used only on packages encountering AM readers during shipment and sale to consumers. Alternatively, the tag could be deployed with the RF circuit activated and the AM circuit not magnetized, i.e., inactive, where only RF readers are present. In this scenario, the AM circuit may be magnetized and activated after the tag has been deployed if necessary. Finally, the tag may be deployed with both the RF and AM portions active and magnetized, respectively. 
   Further, while the present embodiment is an AM/RF hybrid tag that is “passive”, i.e., is incapable of transmitting data itself, merely providing a response (or not) to an interrogating AM or RF signal, it is possible to create other, more complex hybrids using a bias magnet as a shared component between circuits. For example, an AM/RFID hybrid may be created in which an IC/processor, power source and antenna are added to the present arrangement of components. This configuration would allow for the inventive tag to store and potentially transmit additional information apart from the active/inactive information available with exemplary AM/RF hybrid. Thus, with the inclusion of an IC/processor, it is possible for the hybrid/universal tag  100  to actually broadcast product and/or shipping information, similar to known RFID tags, when interrogated via AM or RF protocols. 
   It is also possible for the above-described AM/RF tag  100  to function as, or mimic, an RFID tag, even without the inclusion of an IC/processor. This may be accomplished through the placement of multiple resonator strips of varying lengths, and frequencies, in the bubble pack  160 . As will be appreciated, different resonator strips, each representing differing types of information, e.g., active/passive, manufacturing location, etc., and having a specific resonant frequency, may be stored within the bubble pack  160  for subsequent AM interrogation. It may also be possible to create resonator strips that have coatings (e.g., organic coatings) that only resonate when certain, very specific conditions cause the organic coatings to deteriorate. In this manner, a plurality of interrogation signals can be broadcast at the hybrid tag/assembly  100 , utilizing AM protocols, and the cumulative effect of receiving or not receiving a corresponding signal from each of the resonator strips in the bubble pack  160  effectively mimics the broadcast of multiple data bits from an integrated IC or processor. 
   While the invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various obvious changes may be made, and equivalents may be substituted for elements thereof, without departing from the essential scope of the present invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention includes all embodiments falling within the scope of the appended claims.