Abstract:
Embodiments of the present application relate generally to electronic hardware, computer software, wireless communications, network communications, wearable, hand held, and portable computing devices for facilitating communication of information and presentation of media. An electrically conductive substrate, such as a sheet of metal or metal alloy, for example, includes an active antenna formed by a slot or opening formed in the substrate, and also includes at least one separate passive slot or opening (e.g., a passive slit) formed in the substrate. The active antenna may be intentionally detuned from one or more target frequencies (e.g., 802.11, 2.4 GHz, 5 GHz) such that the active antenna is not optimized (e.g., is not tuned) for the one or more target frequencies. One portion of the active antenna may be electrically coupled with a ground potential. Another portion of the active antenna may be electrically coupled with a RF receiver, transmitter, or transceiver.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to the following applications: U.S. patent application Ser. No. ______, filed on ______, having Attorney Docket No. ALI-233, and titled “RF Architecture Utilizing A MIMO Chipset For Near Field Proximity Sensing And Communication”; U.S. patent application Ser. No. 13/919,307, filed on Jun. 17, 2013, having Attorney Docket No. ALI-206, and titled “Determining Proximity For Devices Interacting With Media Devices”; and U.S. patent application Ser. No. 13/802,646, filed on Mar. 13, 2013, having Attorney Docket No. ALI-230, and titled “Proximity-Based Control Of Media Devices For Media Presentations”; all of which are hereby incorporated by reference in their entirety for all purposes. 
     
    
     FIELD 
       [0002]    These present application relates generally to the field of personal electronics, portable electronics, media presentation devices, audio systems, and more specifically to wirelessly enabled devices that may detect and may wirelessly communicate with one another while disposed in near field RF proximity of one another, including in direct contact with one another. 
       BACKGROUND 
       [0003]    Conventional wireless communication standards, such as those for Bluetooth and WiFi systems (e.g., 802.11xx, 2.4 GHz or 5 GHz bands, etc.) allow for a receiver to measure signal strength from an external RF transmitting source, such as smartphone or other wireless device, for example. One measure of signal strength is received signal strength indication (RSSI). RSSI may be regarded as an indication of RF power being received by an antenna of the receiving wireless device. High RSSI values are indicative of a strong signal and low RSSI values are indicative of a weak signal. In that the RSSI is a relative measure of received signal strength, the units of measure for RSSI may be in arbitrary units. For example, in one application RSSI may be assigned arbitrary units of 0 to 100 or 0 to some maximum value of RSSI. Therefore, units of actual measured power, such as mW or dBm need not be used and may not be helpful in determining relative strength or weakness of received signal strength in a wireless environment. 
         [0004]    In some applications it is desirable to use RSSI to estimate distance between the transmitting device and the receiving device. For example, if the transmitting device and receiving device are approximately 10 cm away from each other, then the RSSI should be stronger than when they are 1 meter away from each other. However, there are known difficulties in using RSSI readings for accurate distance measurements due to many factors including but not limited to: (a) multipath effects caused by RF signal reflection off surrounding objects such as walls, moving objects, and stationary objects; (b) differences in antenna radiation patterns and polarization patterns of the transmitting and receiving antennas; and (c) RF interference generated by other radiators of RF energy in the wireless environment of the receiver that is attempting to measure the RSSI of a specific transmitter; just to name a few. Generally, close distance RSSI measurements may be made with a higher accuracy than long distance measurements due to the inverse square power drop off of the RF signal (i.e., 1/R 2 ) in the far field region and a greater drop off (e.g., greater than 1/R 3 ) in the near field region. Close proximity sensing using RSSI has a statistically higher level of accuracy and a receiving device may infer that it is in close proximity to a transmitting device when both devices are close to one another. However, there remains a small probability that a false alarm may be triggered when the RSSI indicates close proximity when in fact the two devices are not in close proximity to each other. 
         [0005]    Thus, there is a need for systems that allow for accurate RF signal detection to be made in close proximity between transmitting and receiving devices without relying solely on RSSI information or that don&#39;t use RSSI information for determining proximity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Various embodiments or examples (“examples”) of the present application are disclosed in the following detailed description and the accompanying drawings. The drawings are not necessarily to scale: 
           [0007]      FIG. 1A  depicts a top plan view of one example of an active antenna and passive slits formed in a substrate of an electrically conductive material, according to an embodiment of the present application; 
           [0008]      FIG. 1B  depicts a cross-sectional view along line AA-AA of  FIG. 1A  of an active antenna and passive slits formed in a substrate of an electrically conductive material, according to an embodiment of the present application; 
           [0009]      FIG. 1C  depicts an example schematic diagram of electrical connections with the active antenna, according to an embodiment of the present application; 
           [0010]      FIGS. 1D-1G  are top plan views depicting examples of configurations for an active antenna and passive slits formed in a substrate of an electrically conductive material, according to an embodiment of the present application; 
           [0011]      FIGS. 1H-1M  depict examples of different perforate materials for a substrate of an electrically conductive material, according to an embodiment of the present application; 
           [0012]      FIG. 2  depicts an exemplary computer system according to an embodiment of the present application; 
           [0013]      FIGS. 3A-3F  depicts profile views of example configurations of an active antenna and passive slits formed in a substrate of an electrically conductive material that is positioned on a system, according to an embodiment of the present application; 
           [0014]      FIGS. 4A-4B  depict examples of a live device generating a RF signal that may be detected by a system using an active antenna and passive slits, according to an embodiment of the present application; 
           [0015]      FIG. 5  depicts a plot of RSSI measurements for a conventional system that uses an active antenna and does not use passive slits; 
           [0016]      FIG. 6  depicts a plot of RSSI measurements for a system using an active antenna and passive slits, according to an embodiment of the present application; 
           [0017]      FIG. 7  depicts a flow diagram for detecting a live device using a system having an active antenna and passive slits, according to an embodiment of the present application; 
           [0018]      FIG. 8  depicts a flow diagram for detecting a live system using a device having an active antenna and passive slits, according to an embodiment of the present application; 
           [0019]      FIG. 9A  depicts front, side, and back views of a device that includes an active antenna and passive slits, according to an embodiment of the present application; 
           [0020]      FIG. 9B  depicts the device of  FIG. 9A  being positioned directly on top of a live system, according to an embodiment of the present application; 
           [0021]      FIG. 10A  depicts a schematic diagram of one example of an active antenna electrically coupled with a RF system, according to an embodiment of the present application; 
           [0022]      FIG. 10B  depicts a schematic diagram of another example of an active antenna electrically coupled with a RF system, according to an embodiment of the present application; and 
           [0023]      FIGS. 11A-11E  depict different use examples for the active antenna/passive slit detection system, according to an embodiment of the present application. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Various embodiments or examples may be implemented in numerous ways, including as a system, a process, an apparatus, a user interface, or a series of program instructions on a non-transitory computer readable medium such as a computer readable storage medium or a computer network where the program instructions are sent over optical, electronic, or wireless communication links. In general, operations of disclosed processes may be performed in an arbitrary order, unless otherwise provided in the claims. 
         [0025]    A detailed description of one or more examples is provided below along with accompanying drawing FIGS. The detailed description is provided in connection with such examples, but is not limited to any particular example. The scope is limited only by the claims and numerous alternatives, modifications, and equivalents are encompassed. Numerous specific details are set forth in the following description in order to provide a thorough understanding. These details are provided for the purpose of example and the described techniques may be practiced according to the claims without some or all of these specific details. For clarity, technical material that is known in the technical fields related to the examples has not been described in detail to avoid unnecessarily obscuring the description. 
         [0026]      FIG. 1A  depicts a top plan view  190   a  of a substrate of an electrically conductive material  150  in which a plurality of separate apertures (e.g., holes or openings) are formed. Here, those separate apertures are depicted looking down on a surface  151  of the substrate  150 . Therefore, the separate apertures may be described as through holes formed in the substrate  150  and extending all the way through the substrate  150  as will be described in greater detail in  FIG. 1B . 
         [0027]    One or more of the separate apertures comprises an active antenna  100  having a length dimension L that is substantially larger that a width dimension H. For example, if active antenna  100  has the shape of a rectangle as depicted in  FIG. 1A , then H is much less than L (e.g., H&lt;&lt;L), such that if L is 150 mm then H may be 10 mm or less (e.g., H=3.5 mm). Actual shapes and dimensions of the active antenna  100  may be application dependent and are not limited to the configuration depicted in  FIG. 1A  or in any other figures herein. One edge  110  of antenna  100  is electrically coupled with a radio frequency (RF) system (not shown) (e.g., a RF receiver, RF transmitter or RF transceiver) and an opposite edge  112  is electrically coupled with a ground potential (not shown) (e.g., a ground—GND or chassis ground). Edges  110  and  112  are along a length dimension of the active antenna  100 . As one example, a node  111  on edge  110  may be electrically coupled with the RF system and another node  113  on the opposite edge  112  may be electrically coupled with the ground potential. In some examples, the electrical connections for nodes  111  and  113  may be reversed and node  113  electrically coupled with the RF system and node  111  electrical coupled with the ground potential. Although the position of the electrical connections to the edges  110  and  112  are depicted directly opposite each other, that is node  111  is directly opposite node  113 , the nodes may be positioned along their respective edges at other locations and the configuration depicted is a non-limiting example. Although one active antenna  100  is depicted there may be a plurality of active antennas as denoted by  121 . 
         [0028]    Substrate  150  also includes one or more apertures that define a passive slit denoted as  101  and  103 . Although two passive slits ( 101 ,  103 ) are depicted there may be just a single passive slit or more than two passive slits as denoted by  123 . Moreover, the relative position on the substrate  150  of the passive slit(s) and the active antenna(s) are not limited to the configurations depicted in  FIG. 1A  or in other figures herein and the actual size, shape, dimensions, and positions of the passive slit(s) and/or active antenna(s) may be application dependent. Passive slits ( 101 ,  103 ) are not electrically coupled with circuitry, the ground potential, or the RF system. Passive slits ( 101 ,  103 ) are passive structures formed in the substrate  150  and may operate to modify current flow along substrate  150  generated by interaction of an external RF signal with active antenna  100  as will be described below in reference to  FIGS. 4A-6 . Passive slits ( 101 ,  103 ) are not driven by circuitry nor do they generate a signal that is coupled with circuitry. 
         [0029]    Typically, dimensions of the passive slits ( 101 ,  103 ) may be much less than similar dimensions of the active antenna  100 . For example, if the passive slits ( 101 ,  103 ) are rectangular in shape as depicted in  FIG. 1A , then a width dimension W of passive slits ( 101 ,  103 ) may be less than the width dimension H of the active antenna  100 . For example, if H is 5 mm, then W may be 1.5 mm. Moreover, if the length L of the active antenna is 150 mm then length D may be 53 mm for the passive slits ( 101 ,  103 ). In some examples, one or more of the passive slits may have a length D that is not shorter than the length L of the active antenna  100  or D is less than L but not by a large amount, such as when D=53 mm and L=150 mm as in the example above. For example, dimensions of L and D may be: L=170 mm and D=180 mm; or L=130 mm and D=115 mm. Actual dimensions of L and D, and/or H and W will be application dependent and are not limited to the examples described herein. Passive slits ( 101 ,  103 ) may be placed at various positions along surface  151  of substrate  150 , such as opposite ends of active antenna  100 , for example. In that the plurality of apertures are spatially separate from one another, passive slits ( 101 ,  103 ) may be spaced apart from active antenna  100  by a distance S that may be the same or different for each passive slit ( 101 ,  103 ). The active antenna  100  may be tuned to the target frequency or in some examples may be detuned to a frequency range that is below (i.e., lower) that of the target frequency or a frequency range that is above (i.e., greater) that of the target frequency. Therefore, the active antenna  100  may have its dimensions (e.g., the L dimension) selected to tune or to de-tune the active antenna  100  relative to a target frequency, such as a target frequency to be detected by a RF system or RF receiver that is electrically coupled with the active antenna  100 . De-tuning may be above or below the target frequency. Active antenna  100  may have a vertical polarization pattern. Computer aided design (CAD) software, tools, and the like may be used to design and simulate the RF parameters and performance of the active antenna  100  and passive slit ( 101 ,  103 ) for a particular design. CAD tools including but not limited to Method of Moments EM, Momentum 3D Planar EM simulator, and ANSYS Electromagnetic Simulator for RF and antennas may be used. 
         [0030]    In that the active antenna  100  and passive slits ( 101 ,  103 ) are apertures formed in substrate  150 , a void in the opening defined by the apertures, denoted as  102   a  for the active antenna  100  and  102   b  for the passive slits ( 101 ,  103 ), may be occupied by air or some other electrically non-conductive material, medium, dielectric material, or composition of matter. Examples of suitable electrically non-conductive materials includes but is not limited to rubber, plastics, foam, glass, Plexiglas, wood, stone, a gas, paper, inert organic or inorganic materials, cloth, leather, a non-conductive liquid, Teflon, PVDF, minerals, just to name a few. A material that occupies the void/opening may be selected for a functional purpose, an esthetic purpose, or both. In some applications a functional element such as a switch, button, actuator, indicator (e.g., a LED), microphone, transducer, or the like may be positioned in void/opening ( 102   a ,  102   b ). In other applications the material disposed in the void/opening ( 102   a ,  102   b ) may include a logo, a trademark, a service mark, ASCII characters, graphics, patterns, one or more esthetic features, instructions, or the like. 
         [0031]    Moving on to  FIG. 1B , a cross-sectional view  190   b  of the substrate  150  depicts in greater detail the void/opening ( 102   a ,  102   b ) of the apertures for active antenna  100  and passive slits ( 101 ,  103 ). Surfaces  151  and  153  of substrate  150  are depicted as being substantially parallel to each other; however, substrate  150  may have a thickness T that varies and need not be flat, planar, or smooth. Moreover, substrate  150  may have a shape including but not limited to an arcuate shape, curvilinear shape, an undulating shape, and a complex shape, just to name a few. Substrate  150  may be made from a perforate material (see  FIG. 1E ) such as a screen, mesh, or material with perforations in it. 
         [0032]    Attention is now directed to  FIG. 1C  where a schematic diagram  190   c  depicts one example of how the opposing sides ( 110 ,  112 ) along the length L dimension of the active antenna  100  may be electrically coupled. Node  111  on side  110  is electrically coupled  163  with a RF system  160 . The RF system  160 , active antenna  100  and its associated passive slits (e.g.,  101  and  103 ) may also be referred to as a detection system herein. The electrical coupling  163  may be made using a variety of connection techniques including but not limited to a RF feed, coaxial cable, a wire, a shielded connection, an unshielded connection, a partially shielded connection, an electrically conductive trace, just to name a few. A node  165  of the RF system  160  may include a termination device  161 , such as a SMA connector or the like, configured to make an impedance matching termination, such as 50 ohms, for example. Node  113  on side  112  is electrically coupled  171  with a ground potential  170 . The ground potential  170  may include but is not limited to a chassis ground, circuit ground, and power supply ground, just to name a few. The actual selection of the appropriate ground potential may be application dependent and is not limited to the ground potentials described herein. The electrical coupling  171  may use any suitable electrical connection medium including but not limited to wire, a conductive trace, a cable, and a coaxial cable, just to name a few. RF system  160  may include one or more RF devices including but not limited to RF transceivers for WiFi, Bluetooth, Ad Hoc WiFi, RF transceivers, RF receivers, and RF transmitters. RF system  160  may include a RF device configured for and/or devoted to operation with active antenna  100  (e.g., a RF receiver). RF system  160  may generate one or more signals on an output  169  in response to RF signals received by active antenna  100 . 
         [0033]    In  FIG. 1C , an axis X of the active antenna  100  is depicted as being orthogonal to an axis Y of the passive slits ( 101 ,  103 ). However, the configuration depicted is just one non-limiting example and the axis of the active antenna  100  and passive slits ( 101 ,  103 ), if any, need not have a particular angular orientation. For example, angle α as measured between the X and Y axes need not be 90 degrees (e.g., a right angle) and other angular relationships may be used. Furthermore, any angular relationship between axes of the active antenna  100  and the passive slits ( 101 ,  103 ) may vary such that a for  103  may be different than a for  101 . 
         [0034]      FIGS. 1D-1G  depict top plan views of examples  190   d - 190   g  for different configurations for an active antenna  100  and passive slits ( 101 ,  103 ) formed in a substrate  150  and different configurations for the substrate  150 . The examples depicted are non-exhaustive and non-limiting examples of different configurations that may be used. Moreover, the examples may include more or fewer active antennas and passive slits than depicted in  FIGS. 1D-1G . In  FIG. 1D , example  190   d  depicts a substrate  150  that includes two active antennas ( 100   a ,  100   b ) having a rectangular shape and two passive slits  101  and  103  having a “X” shape. Moreover, there is no particular symmetrical relationship between the active antennas ( 100   a ,  100   b ) and passive slits ( 101 ,  103 ). In  FIG. 1E , example  190   e  depicts a substrate  150  comprised of a perforate article having a plurality of perforations  170  (e.g., through holes) distributed across its surface  151 . Perforations  170  are substantially smaller than the plurality of separate apertures for the active antenna  100  and cross-shaped “+” passive slits ( 101 ,  103 ).  FIGS. 1H-1M  depict other non-limiting examples of substrates  150   h - 150   m  comprised of perforate materials having perforations similar to perforations  170 . 
         [0035]      FIG. 1F  depicts an example  190   f  in which there is one active antenna  100  having a rectangular shape and a plurality of passive slits ( 101   a ,  101   b ,  103   a ,  103   b ) having a chevron shape. In  FIG. 1G , example  190   g  depicts a substrate  150  having two rectangular shaped passive slits ( 101 ,  103 ) and an active antenna  100  having a complex shape configured to match a contour of one or more elements  131   a - 131   f  that are positioned in the aperture  102   a  (e.g., void/opening) of active antenna  100 . As one example, elements  131   a - 131   f  may be switches electrically coupled with circuitry of a device or system (not shown) that includes the substrate  150 . Elements  131   a - 131   f  may be made from an electrically non-conductive material such as rubber, plastic, or a dielectric material, for example. Aperture  102   a  may be filled with the material used for the elements  131   a - 131   f  or may be a combination of air and the material used for the elements  131   a - 131   f , for example. Examples of functional roles for elements  131   a - 131   f  include but are not limited to:  131   a  “+” for volume up;  131   b  “−” for volume down;  131   c  to go forward one track in a playback of content;  131   d  to go back one track in a playback of content;  131   e  to commence playback of content; and  131   f  to stop or halt playback of content. One or more of the elements  131   a - 131   f  may serve multiple functions, such as element  131   f  functioning to stop or halt playback of content when pressed by a user&#39;s fingers and also functioning to pair a system that includes the substrate  150  with another wireless device, such as Bluetooth paring of devices, for example. Aperture  102   a  may include other elements such as element  131   g  that may be operative as an indicator light (e.g., LED) to indicate status such as “power on”, “paring mode”, or “standby mode”, for example. Element  131   g  may be a microphone or other type of transducer, for example. 
         [0036]      FIG. 2  depicts an exemplary computer system  200  suitable for use in the systems, methods, and apparatus described herein. In some examples, computer system  200  may be used to implement circuitry, computer programs, applications (e.g., APP&#39;s), configurations (e.g., CFG&#39;s), methods, processes, or other hardware and/or software to perform the above-described techniques. Computer system  200  includes a bus  202  or other communication mechanism for communicating information, which interconnects subsystems and devices, such as one or more processors  204 , system memory  206  (e.g., RAM, SRAM, DRAM, Flash), storage device  208  (e.g., Flash, ROM), disk drive  210  (e.g., magnetic, optical, solid state), communication interface  212  (e.g., modem, Ethernet, WiFi), display  214  (e.g., CRT, LCD, touch screen), one or more input devices  216  (e.g., keyboard, stylus, touch screen display), cursor control  218  (e.g., mouse, trackball, stylus), one or more peripherals  240 . Some of the elements depicted in computer system  200  may be optional, such as elements  214 - 218  and  240 , for example and computer system  200  need not include all of the elements depicted. 
         [0037]    According to some examples, computer system  200  performs specific operations by processor  204  executing one or more sequences of one or more instructions stored in system memory  206 . Such instructions may be read into system memory  206  from another non-transitory computer readable medium, such as storage device  208  or disk drive  210  (e.g., a HD or SSD). In some examples, circuitry may be used in place of or in combination with software instructions for implementation. The term “non-transitory computer readable medium” refers to any tangible medium that participates in providing instructions to processor  204  for execution. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media includes, for example, optical, magnetic, or solid state disks, such as disk drive  210 . Volatile media includes dynamic memory, such as system memory  206 . Common forms of non-transitory computer readable media includes, for example, floppy disk, flexible disk, hard disk, SSD, magnetic tape, any other magnetic medium, CD-ROM, DVD-ROM, Blu-Ray ROM, USB thumb drive, SD Card, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, or any other medium from which a computer may read. 
         [0038]    Instructions may further be transmitted or received using a transmission medium. The term “transmission medium” may include any tangible or intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine, and includes digital or analog communications signals or other intangible medium to facilitate communication of such instructions. Transmission media includes coaxial cables, copper wire, and fiber optics, including wires that comprise bus  202  for transmitting a computer data signal. In some examples, execution of the sequences of instructions may be performed by a single computer system  200 . According to some examples, two or more computer systems  200  coupled by communication link  220  (e.g., LAN, Ethernet, PSTN, or wireless network) may perform the sequence of instructions in coordination with one another. Computer system  200  may transmit and receive messages, data, and instructions, including programs, (i.e., application code), through communication link  220  and communication interface  212 . Received program code may be executed by processor  204  as it is received, and/or stored in a drive unit  210  (e.g., a SSD or HD) or other non-volatile storage for later execution. Computer system  200  may optionally include one or more wireless systems  213  in communication with the communication interface  212  and coupled ( 215 ,  223 ) with one or more antennas ( 217 ,  225 ) for receiving and/or transmitting RF signals ( 221 ,  227 ), such as from a WiFi network, BT radio, or other wireless network and/or wireless devices, for example. Examples of wireless devices include but are not limited to: a data capable strap band, wristband, wristwatch, digital watch, or wireless activity monitoring and reporting device; a smartphone; cellular phone; tablet; tablet computer; pad device (e.g., an iPad); touch screen device; touch screen computer; laptop computer; personal computer; server; personal digital assistant (PDA); portable gaming device; a mobile electronic device; and a wireless media device, just to name a few. Computer system  200  in part or whole may be used to implement one or more systems, devices, or methods using the active antenna  100  and passive slits ( 101 ,  103 ) as described herein. For example, a radio (e.g., a RF receiver) in wireless system(s)  213  may be electrically coupled  231  with an edge  110  (e.g., at  111  or other location on the edge) of the active antenna  100 . Computer system  200  in part or whole may be used to implement a remote server or other compute engine in communication with systems, devices, or method using the active antenna  100  and passive slits ( 101 ,  103 ) as described herein. 
         [0039]    Reference is now made to  FIGS. 3A through 3F  where profile views of example configurations of an active antenna and passive slits formed in a substrate of an electrically conductive material are depicted. In  FIG. 3A , a system  300   a  includes a many sided enclosure  310  (e.g., a chassis or housing) including on at least two of its side the substrate  150  of an electrically conductive material and other sides, such as side  301  that are made from a non-electrically conductive material. The side  301  is electrically non-conductive as may be the case for other sides not visible in  FIG. 3A . Here, passive slits ( 101 ,  103 ) and active antenna  100  are formed in surface  151   a  of one of the sides of the substrate  150 . Although enclosure  310  is depicted as having a box or rectangular shape, the actual shape of enclosure  310  will be application dependent and is not limited to the shapes depicted in  FIGS. 3A-3F . Enclosure  310  of system  300   a  may serve many functions, such as a wireless speaker media/content playback system that may connect with or otherwise pair with other wireless devices to negotiate content transfer to/from the other wireless devices, for example. RF system  160  in conjunction with passive slits ( 101 ,  103 ) and active antenna  100  may be used to detect RF signals transmitted by the other wireless devices when those devices are positioned directly on surface  151   a  or positioned in near field proximity or very close near field proximity of substrate  150  (e.g. surface  151   a ). Very close near field proximity may comprise a distance from the substrate where the passive slits ( 101 ,  103 ) and active antenna  100  are positioned that is approximately 0.5 meters or less. More preferably, 50 mm or less. Even more preferably, 30 mm or less. Near field proximity may comprise a distance that is greater than 0.5 meters. The foregoing are non-limiting examples of what may define near field proximity or very close near field proximity and actual values will be application dependent. 
         [0040]    In  FIG. 3B , system  300   b  includes an enclosure  310  in which the passive slits ( 101 ,  103 ) and active antenna  100  are positioned on a different side of the enclosure  310 . A side  311  of enclosure  310  is electrically non-conductive and other sides not visible in  FIG. 3B  may also be electrically non-conductive. Here, surface  151   b  of substrate  150  includes the passive slits ( 101 ,  103 ) and active antenna  100 . Therefore, the passive slits ( 101 ,  103 ) and active antenna  100  may be positioned on the substrate  150  in a variety of configurations that may be determined on an application specific basis. 
         [0041]    In  FIG. 3C , system  300   c  includes an enclosure  310  having a cylindrical shape. A side  321  is electrically non-conductive and surface  150  includes the passive slits ( 101 ,  103 ) and active antenna  100 . Therefore, surface  150  and its corresponding passive slits ( 101 ,  103 ) and active antenna  100  may have an arcuate shape or other non-linear or curvilinear shape. The side  321  is electrically non-conductive as may be the case for other sides not visible in  FIG. 3C . 
         [0042]    In  FIG. 3D , a system  300   d  includes four (4) passive slits ( 101 ,  103 ,  301 ,  303 ) formed in substrate  150  which spans several sides of enclosure  310 . A side  331  is electrically non-conductive as may be the case for other sides not visible in  FIG. 3D . Passive slits  101  and  103  span two different sides of substrate  150  and are formed on surfaces  151   a  and  151   b ; whereas, passive slits  301  and  303  are formed only on one side of substrate  150  and are formed in surface  151   a  along with a single active antenna  100 . 
         [0043]    In  FIG. 3E , a system  300   e  includes an enclosure  310  in which surfaces  151   a  and  151   b  have a portion of active antenna  100  formed therein. Moreover, substrate  150  includes two passive slits formed on different sides of the enclosure  310 , with one of the slits  103  formed in surface  151   b  and the other slit formed in surface  151   a . A side  341  is electrically non-conductive as may be the case for other sides not visible in  FIG. 3E . 
         [0044]    In  FIG. 3F , a system  300   f  includes a substrate  150  having four passive slits ( 101   c ,  101   d ,  103   c ,  103   d ) and an active antenna  100  having a complex profile (e.g., along its perimeter  100   p ). Sides  351  are electrically non-conductive as may be the case for other sides not visible in  FIG. 3F . Due to the complex profile of active antenna  100 , the location of the opposing sides is not as straight forward as in the case where the active antenna  100  has a regular shape (e.g., a rectangle). Here, opposing sides  110  and  112  vary in distance from each other along the perimeter  100   p  (shown in dashed line). Accordingly, the points along the edges for positioning the nodes  111  and  113  may be a matter of design choice. For example, nodes  111  and  113  may be positioned at a narrow portion of the active antenna  100  were the opposing sides are closest to each other. Here, in this example where the active antenna  100  has a complex shape, a distance  100   e  around the perimeter  100   p  may be selected so that the active antenna  100  may be detuned from a target frequency by at least a wavelength of the target frequency divided by two (e.g., A/ 2 ). In other examples, the dimensions of the active antenna  100  (e.g., the length) may be selected to tune the active antenna  100  to a target frequency. The target frequency will be application dependent and the active antenna  100  and passive slits ( 101 ,  103 ) may be designed to accommodate the needs of specific design goals for each application. Examples of target frequencies include but are not limited to: 2.4 GHz; 2.4 GHz-2.48 GHz; from about 2.4 GHz to about 2.48 GHz; 5 GHz; unlicensed bands, licensed bands, cellular bands, bands used by 2G, 3G, 4G, and 5G devices, Bluetooth bands, any of the 802.11 bands, military bands, just to name a few. The active antenna  100  may be tuned to the target frequency or in some examples may be detuned to a frequency range that is below that (i.e., lower) of the target frequency or a frequency range that is above (i.e., greater) that of the target frequency. 
         [0045]    Turning now to  FIGS. 4A-4B  were examples of a live device generating a RF signal that may be detected by a system using an active antenna and passive slits are depicted. In  FIGS. 4A-4B , nodes  111  and  113  may be connected as described in reference to  FIG. 1C  above. A live device  450  is transmitting Tx a RF signal  453 . There may also be other RF sources in an environment in which the live device  450  and/or substrate  150  (and its associated system) reside and those RF sources are denoted as transmitting Tx sources  461   a - 461   n . For purpose of discussion, a live device may be, without limitation, a device that is actively transmitting Tx a RF signal or may be activated (e.g., turned on, controlled or commanded) to transmit Tx a RF signal. As one example, a smartphone transmitting Tx RF using any one of its radios (BT, WiFi, 3G, 4G, 5G, 802.11, etc.) may be a live device. If the smartphone is powered off or in airplane mode, where it is not transmitting Tx RF, then the smartphone may not be a live device. 
         [0046]    In  FIGS. 4A-4B , live device  450  is placed  451  directly on surface  151  of substrate  150  at a rightmost end of the substrate  150  as denoted by point 0. The live device  450  is translated T (e.g., moved) across the surface  151  in increments of 25 mm denoted by M until it reaches the end of the substrate  150  as denoted by point N. At each increment along the path of translation T, the live device  450  is rotated R about an axis Y a full 360 degrees in increments of 45 degrees (e.g., eight increments). The RF transmission Tx  453  from live device  450  is received as RF signal Rx  453  by the active antenna  100  and stimulates the active antenna  100  to generate a signal that is detected by RF system  160 . A signal generated by RF system  160  on its output  169  may be measured (e.g., using test equipment) to determine RF signal strength received by active antenna  100  from the live device  450  at different increments of angular rotation R and translation distance T along the substrate  150  (e.g., from 0 to N=250 mm). Accordingly, while the live device  450  is placed at position 0, eight measurements may be taken for angular increments of 0 deg, 45 deg, 90 deg, 135 deg, 180 deg, 225 deg, 270 deg, and 325 deg. Those measurements may be repeated for each 25 mm increment along the translation path T. The above mentioned increments are non-limiting examples and other increments may be used. 
         [0047]    In the cross-sectional view of  FIG. 4B , live device  450  is depicted in its most preferred placement, which is directly on the surface  151  of substrate  150 . However, in some applications the live device  450  may be placed above the surface  151  at a distance  470  that is in very close near field proximity of the surface  151  of the substrate  150  and its associated active antenna  100  and passive slits ( 101 ,  103 ). Although the received RF signal Rx  453  may be at its strongest when the live device is at 470=0 (e.g., directly on surface  151 ), there may be circumstances where the live device is positioned in very close near field proximity of the surface  151 . In the very near field region, the drop off or RF signal strength may be larger than the well understood 1/R 2  drop off rate, and the drop off may be 1/R 3  or 1/R 4 . Therefore, even small distances from surface  151  may result in a large drop off in RF signal strength as received by active antenna  100  and detected by RF system  160 . Distance  470  is preferably 0.5 meters or less, more preferably 50 mm or less, and even more preferably 30 mm or less. Actual distances for very close near field proximity will be application dependent and are not limited to the examples described herein. The live device  450  may comprise a wide variety of wirelessly enabled devices including but not limited to a smartphone, gaming device, tablet or pad, wireless headset or earpiece, a laptop computer, an image capture device, a wireless wristwatch or timepiece, a data capable strapband or wristband, just to name a few. 
         [0048]    Attention is now directed to  FIG. 5  which depicts a plot  500  of RSSI measurements for a conventional system that uses an active antenna and does not use passive slits. On a y-axis of plot  500 , a received signal strength indication (RSSI) is measured in units of dBm and on an x-axis distance from a right edge of a substrate of electrically conductive material that only has a single aperture that defines a single active antenna. The substrate sans the passive slits RSSI loss below −20 dBm at the 0 mm position at the right most edge of the substrate as denoted by the region  501  in dashed line. Here, at 0 mm when the live device is rotated about its axis to the 180 degree and 225 degree positions, the RSSI is below −35 dBm at 180 degrees and is below −25 dBm at 180 degrees. Similarly, in region  502  between the 225 mm and 250 mm positions near the left end of the substrate, at the 225 mm position the 0 degree and 180 degree rotational positions result in RSSI that is almost at −35 dBm. At the 250 mm position, the 0 degree rotational position yields a RSSI that about below −27 dBm. 
         [0049]    Looking now at  FIG. 6 , an improvement in RSSI at the 0 mm, 225 mm and 250 mm positions on the substrate  150  that includes the active antenna  100  and the passive slits ( 101 ,  103 ), as depicted in  FIGS. 4A-4B , is shown. In  FIG. 6 , in a region  601  at the 0 mm position at the rightmost end of the substrate  150 , for all angular rotations between 0 degrees and 315 degrees, measured RSSI does not fall below −20 dBm for any angular position of the live device  450 . The measured RSSI shows an improvement of approximately 17 db for the 180 degree position and approximately 6 dB for the 225 degree position when compared to the conventional no-passive slit configuration plotted in  FIG. 5 . In a region  503 , at the 225 mm and 250 mm positions towards the leftmost end of the substrate  150 , for all angular rotations between 0 degrees and 315 degrees, measured RSSI does not fall below −25 dBm for any angular position of the live device  450 . At the 180 degree rotation at the 225 mm position, RSSI improved by approximately −20 dBm. At the 180 degree rotation at the 250 mm position, RSSI decreased by approximately 7 dB at just slightly below the 20 dBm line on the plot. At the 0 degree rotation at the 225 mm position, the RSSI improved by approximately 15 dB, and at the 250 mm position the RSSI improved by approximately 5 dBm. 
         [0050]    The live device when placed directly on top of the substrate of  FIG. 5  shows a larger positional dependency at the right and left ends of the substrate as highlighted in the regions  501  and  503 . Therefore, a user who places his/her live device at the ends of the substrate may not have the RF signal emitted by the live device be detected by the substrate having only the active antenna. Accordingly, the user may have to consciously avoid certain portions and angular orientations of the live device on the substrate in order to get accurate detections of RF emissions from the live device. 
         [0051]    Ideally, the most straight forward and easy to remember use scenario for a user may be a simple instruction to place the live device  450  anywhere on the surface  151  of the substrate  150  regardless of angular orientation of the live device, in order to have the RF emissions from the users device detected by the active antenna  100  used in conjunction with the passive slits ( 101 ,  103 ). The plot  600  of  FIG. 6  and the depictions in  FIGS. 4A-4B  improve measured RSSI and allow for reduction or elimination of placement errors that may lead to low RSSI and failure to detect a live device  450  even thou it has been placed directly on the surface  151  of the substrate  150 . 
         [0052]      FIG. 7  depicts a flow diagram  700  for detecting a live device (e.g., device  450 ) using a system having an active antenna  100  and one or more passive slits ( 101 ,  103 ). At a stage  701  a detection system is activated. The detection system may comprise the substrate  150  and its corresponding active antenna  100 , passive slits ( 101 ,  103 ), and RF system  160 . Activation may comprise powering up or signaling a system or portions of the system that includes the detection system. Activation places the system in readiness to detect RF signals from live devices placed on or in very close near field proximity of the substrate  150 . At a stage  703  a live device is positioned directly on or in very close near field proximity to the detection system. At a stage  705  a determination may be made by the detection system or other system as to whether or not a RF signal from the live device has been detected by the detection system (e.g., RF system  160 ). If no RF signal is detected, then a NO branch may be taken back to a prior stage, such as the stage  703  to retry the process. If the RF signal is detected by the detection system, then a YES branch may be taken to a stage  707 . At the stage  707  an action may be taken based on having detected the RF signal. The action that is taken will be application dependent. The action taken may be implemented using circuitry, hardware, software fixed in a non-transitory computer readable medium, or any combination thereof. As one example, the action taken may be to signal the RF system to activate a RF transceiver into a sniffing mode to begin sniffing packets from WiFi devices. WiFi devices having the strongest RSSI above a predetermined threshold (e.g., the live device  450  because it is right on top of the detection system) may be selected for further analysis, while others with WiFi devices below the threshold may be ignored. As another example, the action may comprise establishing wireless link with the live device and transferring content handling from the live device to a system or device that incorporates or uses the detection system. In some applications, the action taken may be to have the live device and a system/device that includes the RF system  160  and active antenna  100  to use the active antenna  100  to both Tx and Rx with the live device while the live device is still positioned directly on top of substrate or within near or very near field proximity, for example. Data that may be communicated during the Tx and Rx may include but is not limited to: wireless network names and passwords, user names and passwords necessary to access content the live device will hand over to the system/device for handling; locations (e.g., in data storage or the Cloud) for playlists and/or content, just to name a few. Active antenna  100  may be used to Tx at a very low power level so that other RF systems positioned beyond the near field region (e.g., &gt;1 meter) may not be able to detect the transmissions from active antenna  100  due to low signal strength. 
         [0053]      FIG. 8  depicts a flow diagram  800  for detecting a live system using a device having an active antenna  100  and one or more passive slits ( 101 ,  103 ). At a stage  801  a device&#39;s detection system is activated. For example, the detection system may be includes in user device such as a smartphone, tablet, or pad, just to name a few. The user device may include the detection system having the substrate  150  and its corresponding active antenna  100 , passive slits ( 101 ,  103 ), and RF system  160 . At a stage  803  the device (e.g., a user device) is positioned directly on or in very close near field proximity of a live system. The live system may be any device, system or apparatus that generates, communicates, or networks using RF signals that may be detected and acted on by the device (e.g., a user device). At a stage  805 , a determination may be made by the detection system or other system as to whether or not a RF signal from the live system has been detected by the detection system. If no RF signal is detected, then a NO branch may be taken back to a prior stage, such as the stage  803  to retry the process. If the RF signal is detected by the detection system, then a YES branch may be taken to a stage  807 . At the stage  807  an action may be taken based on having detected the RF signal. The action that is taken will be application dependent. The action taken may be implemented using circuitry, hardware, software fixed in a non-transitory computer readable medium, or any combination thereof. As one example, the action taken may be to allow access to some structure or property such as an automobile, a garage, a door, a vault, a safe, an elevator, a turn style, an electronic device or system, a kiosk, just to name a few. The action taken may be similar to or identical to the actions described above for flow  700  of  FIG. 7 . 
         [0054]      FIG. 9A  depicts front, side, and back views of a device  900  that includes an active antenna  100  and one or more passive slits ( 101 ,  103 ) and may be used for the device (e.g., user device) described above in flow  800  of  FIG. 8 . The active antenna  100  and one or more passive slits ( 101 ,  103 ) may be positioned on a front side  901  of device  900 , a back side  903 , a side  902 , or some combination thereof. If the side  902  is not big enough to accommodate all of the elements of the detection system, such as both the active antenna  100  and the passive slits ( 101 ,  103 ), then at least some of those elements may be positioned on the side  902 , such as the active antenna  100 . 
         [0055]    A display  907  on front side  901  of device  900  may be configured to include the active antenna  100  and one or more passive slits ( 101 ,  103 ) formed in an optically transparent and electrically conductive electrode material printed or otherwise formed on the display  907 . Appropriate electrical connections between the opposed edges of the active antenna  100  may be made to the RF system and ground potential as described above. The back side  903  of the device  900  may be configured to include the active antenna  100  and one or more passive slits ( 101 ,  103 ) formed on an appropriate electrically conductive material for the substrate (e.g., substrate  150 ). Similarly, an appropriate material may be used to form active antenna  100 , the passive slits ( 101 ,  103 ), or both on the sides  902  of device  900 . In some examples, the active antenna  100  and one or more passive slits ( 101 ,  103 ) may be formed on multiple sides of the device  900 , such as the front  901  and the back  903 . 
         [0056]      FIG. 9B  depicts the device  900  of  FIG. 9A  being positioned  910  directly on top of a live system  950 . Here, back side  903  of device  900  is positioned directly on a surface  951  of the live system  950  which is actively transmitting Tx and RF signal  953  from an antenna  955  that is electrically coupled  957  with a RF system (not shown) of the live system  950 . When positioned directly on top of the live system  950 , the active antenna  100 , the passive slits ( 101 ,  103 ) on the back side  903  are positioned to detect the RF signal  953 . 
         [0057]      FIG. 10A  depicts a schematic diagram  1000   a  of one example of an active antenna  100  electrically coupled with a RF system  1010 . RF system  1010  may optionally include a switch  1012  that in response to a signal  1009  may connect or disconnect the active antenna  100  from a RF receiver  1014 . The RF system  1010  may not include the switch  1012 , in which case, the active antenna  100  may be directly coupled with the RF receiver  1014 . RF receiver  1014  may generate a signal  1015  internal to RF system  1010 , a signal  1017  external to RF system  1010 , or both in response to signals generate by RF signals Rx  1053  received by or incident on active antenna  100 . A computer system such as that described above in reference to  FIG. 2  may take some action based on one or more of the signals ( 1015 ,  1017 ).  FIG. 10A  depicts a receive only mode for the active antenna  100 . 
         [0058]      FIG. 10B  depicts a schematic diagram  1000   b  of another example of an active antenna  100  electrically coupled with a RF system  1020 . Here, active antenna  100  is electrically couples with a switch  1022  that is responsive to one or more signals  1029  that activate the switch  1022  to couple the active antenna  100  with a RF receiver  1024  configured to detect signals caused by RF signals Rx  1053  received by or incident on active antenna  100 , or to couple active antenna  100  with a RF transmitter  1026  configured to receive a signal  1029  and to cause the active antenna  100  to transmit RF signal Tx  1057  based on the signal  1029 . RF receiver  1024  may generate a signal  1025  internal to RF system  1020 , a signal  1027  external to RF system  1020 , or both in response to signals generate by RF signals Rx  1053  received by or incident on active antenna  100 . A computer system such as that described above in reference to  FIG. 2  may take some action based on one or more of the signals ( 1025 ,  1025 ) and may generate the signal  1029  to be transmitted by active antenna  100 . 
         [0059]      FIGS. 11A-11E  depict different use examples  1100   a - 1100   e  for the active antenna/passive slit detection systems described above. In  FIGS. 11A-11E , actions may be taken by detection systems, live systems, live devices, or any combination of the aforementioned. In  FIG. 11A  a vehicle  1110  may include a detection system denoted as R positioned at various locations on the vehicle  1110 . The detection system in R may comprise the active antenna  100 , the passive slits ( 101 ,  103 ) and the RF system  160 . A live device  1103  is transmitting Tx a RF signal and is positioned  1105  in direct or in very close near field proximity to detection system R, causing one or more actions to be taken, such as unlocking the vehicle, starting the vehicle, arming/disarming the alarm on the vehicle, causing content handling on live device  1104  to be transferred to a system of the vehicle, just to name a few. The detection system R may be disposed on a door, glass or plastic surface of the vehicle  1110  or some other structure, such as a windshield, a door, door glass, a dashboard, a door panel, a console, for example. 
         [0060]    In  FIG. 11B , the detection system R may be incorporated into a display  1121  of a smart TV  1120  and a live device  1103  when positioned  1105  in direct or in very close near field proximity to detection system R cause one or more actions to be taken by smart TV  1120  such as turning the smart TV  1120  on, allowing live device  1103  to control the smart TV  1120  (e.g., as a remote control), or causing the handling of content to be transferred from live device  1103  to the smart TV  1120 , for example. 
         [0061]    In  FIG. 11C , the detection system R may be incorporated into a door  1131  or control panel  1132  of an elevator  1130  or similar conveyance. A live device  1103  when positioned  1105  in direct or in very close near field proximity to detection system R cause one or more actions to be taken by elevator  1130 , such as allowing access to the elevator  1130 , handshaking with the live device  1103  to determine which floor the elevator will transport a user to, transferring maintenance information/records from the elevator  1130  to the live device  1103 , for example. 
         [0062]    In  FIG. 11D , a kiosk  1140  includes a live system S that transmits Tx a RF signal and device  1104  includes a detection system R that when positioned  1107  in direct or in very close near field proximity to live system S cause an action to be taken by the kiosk  1140 , the device  1104 , or both. For example, the action may be to cause the kiosk  1140  to print a ticket or boarding pass, to wirelessly transfer a ticket or boarding pass in digital form to the device  1104 , download or transfer content/information from the kiosk  1140  to the device  1104 , to allow access to a restricted area, transfer wireless network access information to the device  1104 , just to name a few. 
         [0063]    In  FIG. 11E , a laptop  1150  includes a live system S that is transmitting Tx an RF signal. Device  1104  includes a detection system R that when positioned  1107  in direct or in very close near field proximity to live system S cause an action to be taken by the laptop  1150 , the device  1104 , or both. Here, the action taken my be to download images from the device  1104  to a storage system on the laptop  1150 , to unlock or wake up the laptop  1150 , cause the laptop to shut down or logoff for security purposes, cause the laptop  1150  to download content from the Internet based on a list stored in the device  1104 , just to name a few. The examples depicted in  FIGS. 11A-11E  are non-limiting examples and the detection system R may be included in a variety of systems, devices, and structures such as a structure operative as a table, desk, counter, cabinet, window, a display screen, just to name a few. 
         [0064]    The material for the substrate  150  may include any electrically conductive material including but not limited to metals, metal alloys, electrically conductive films, paints, and inks, PC boards, flexible PC boards, electrically conductive materials that can be printed on, painted on, screen printed on or otherwise formed or deposited on a substrate. The separate apertures for the active antenna  100  and passive slits ( 101 ,  103 ) may be formed by process including but not limited to etching, milling, cutting, sawing, drilling, punching, stamping, laser cutting, high pressure water cutting, just to name a few. 
         [0065]    The systems, wireless media devices, apparatus and methods of the foregoing examples may be embodied and/or implemented at least in part as a machine configured to receive a non-transitory computer-readable medium storing computer-readable instructions. The instructions may be executed by computer-executable components preferably integrated with the application, server, network, website, web browser, hardware/firmware/software elements of a user computer or electronic device, or any suitable combination thereof. Other systems and methods of the embodiment may be embodied and/or implemented at least in part as a machine configured to receive a non-transitory computer-readable medium storing computer-readable instructions. The instructions are preferably executed by computer-executable components preferably integrated by computer-executable components preferably integrated with apparatuses and networks of the type described above. The non-transitory computer-readable medium may be stored on any suitable computer readable media such as RAMs, ROMs, Flash memory, EEPROMs, optical devices (CD, DVD or Blu-Ray), hard drives (HD), solid state drives (SSD), floppy drives, or any suitable device. The computer-executable component may preferably be a processor but any suitable dedicated hardware device may (alternatively or additionally) execute the instructions. 
         [0066]    As a person skilled in the art will recognize from the previous detailed description and from the drawing FIGS. and claims set forth below, modifications and changes may be made to the embodiments of the present application without departing from the scope of this present application as defined in the following claims. 
         [0067]    Although the foregoing examples have been described in some detail for purposes of clarity of understanding, the above-described inventive techniques are not limited to the details provided. There are many alternative ways of implementing the above-described techniques or the present application. The disclosed examples are illustrative and not restrictive.