Multi-Element RFID Coupler

Abstract

An RFID communication system comprising a near field coupler that is capable of selectively communicating with a targeted transponder positioned among a group of multiple adjacent transponders. The coupler is configured to receive communication signals from a transceiver and transmit the signals to a targeted transponder in a transponder operating region. The coupler includes a number of radiating elements spaced apart and a switching element. The switching element selectively couples one or more of the radiating elements to the transceiver. The coupled elements transmit the signals into the transponder operating region by emanating a near field effect. The pattern of the near field effect may be adjusted by changing the combination of the coupled radiating elements.

1 - 17 . (canceled) 
     
     
         18 . A near-field coupling device for coupling a transceiver with a targeted transponder, the near-field coupling device comprising:
 a ground plane;   a dielectric substrate adjacent to the ground plane;   a terminating load;   a first radiating element adjacent the dielectric substrate and extending from a port end to a loaded end and connected to the terminating load;   a second radiating element adjacent the dielectric substrate and extending from the port end to the loaded end and connected to the terminating load; and   at least one switching element for selectively electrically connecting one or more of the first and second radiating elements with the transceiver to define a total characteristic impedance of connected radiating elements, wherein in a first configuration of the switching element, the total characteristic impedance of the connected radiating elements is greater than the terminating load and, in a second configuration of the switching element, the total characteristic impedance of the connected radiating elements is less than the terminating load.   
     
     
         19 . The near-field coupling device of  claim 18 , wherein the first radiating element has a length of one half-wavelength or multiple thereof and having a first impedance. 
     
     
         20 . The near-field coupling device of  claim 18 , wherein the second radiating element has a length of one half-wavelength or multiple thereof and having a second impedance. 
     
     
         21 . The near-field coupling device of  claim 18  further comprising one or more additional radiating elements, wherein the at least one switching element is further configured to selectively connect the additional radiating elements and further adjust the total characteristic impedance of the connected radiating elements. 
     
     
         22 . The near-field coupling device of  claim 18 , wherein the first and second radiating elements are parallel and each defines a linear shape. 
     
     
         23 . The near-field coupling device of  claim 18 , wherein the first and second radiating elements are parallel and each defines a zig-zag shape. 
     
     
         24 . The near field coupler according to  claim 18 , wherein the at least one switching element is comprised of a plurality of switches. 
     
     
         25 . The near field coupler according to  claim 24 , wherein the plurality of switches includes a number of switches that is equal to or less than a number of radiating elements. 
     
     
         26 . The near field coupler according to  claim 24 , wherein at least one of the plurality of switches is a PIN diode. 
     
     
         27 . The near field coupler according to  claim 18 , wherein the plurality of radiating elements includes three radiating elements and each radiating element is a radiating element disposed on a first surface of a dielectric substrate. 
     
     
         28 . The near-field coupling device of  claim 18 , wherein the first and second radiating elements are configured to generate an electromagnetic field and are capable of activating a targeted transponder as the targeted transponder moves through the electromagnetic field. 
     
     
         29 . An apparatus comprising a processor, the processor configured to:
 receive indications of at least one of a transponder configuration and a transponder position; and   connect one or more radiating elements of a near-field coupling device depending on at least one of the transponder configuration and a transponder position to configure an impedance ratio between the one or more connected radiating elements and a terminating load of the near-field coupling device.   
     
     
         30 . The apparatus of  claim 29 , wherein the processor configured to connect the one or more radiating elements includes configuring the near-field coupling device to have a total characteristic impedance greater than the terminating load. 
     
     
         31 . The apparatus of  claim 29 , wherein the processor configured to connect the one or more radiating elements includes being configured to connect the one or more radiating elements to configure a total characteristic impedance to be less than the terminating load. 
     
     
         32 . The apparatus of  claim 29 , wherein the processor being configured to connect the one or more radiating elements includes being configured to connect the one or more radiating elements by controlling a respective switching device associated with the one or more radiating elements. 
     
     
         33 . The apparatus of  claim 29 , wherein the processor is further configured to encode one or more transponders by providing RF power transmission to a port of the near-field coupling device. 
     
     
         34 . A method comprising:
 receiving indications of at least one of a transponder configuration and a transponder position; and   connecting one or more radiating elements of a near-field coupling device based on at least the transponder configuration and a transponder position to configure an impedance ratio between the one or more connected radiating elements and a terminating load of the near-field coupling device.   
     
     
         35 . The method of  claim 34 , wherein connecting the one or more radiating elements includes configuring the total characteristic impedance of the near-field coupling device to be greater than the terminating load. 
     
     
         36 . The method of  claim 34 , wherein connecting the one or more radiating elements includes configuring the total characteristic impedance of the near-field coupling device to be less than the terminating load. 
     
     
         37 . The method of  claim 34 , wherein connecting the one or more radiating elements includes being configured to connect the one or more radiating elements by controlling a respective switching device associated with the one or more radiating elements. 
     
     
         38 . The method of  claim 34  further comprising encoding one or more transponders by providing for transmission of a signal to a port of the near-field coupling device.