Multi-element RFID coupler

1. A near field coupler comprising:

a dielectric substrate having a first surface, a second surface, a first end and a second end;

a terminating resistor disposed on the dielectric substrate adjacent the second end;

a ground plane adjacent to the second surface of the dielectric substrate,

a plurality of radiating elements extending proximately from the first end to the second end of the dielectric substrate along the first surface, wherein each of the plurality of radiating elements has a length of one-half wavelength or integer multiple thereof and is connected to the ground plane through the terminating resistor such that each of the plurality of radiating elements and the ground plane together form a one-half wavelength or integer multiple thereof transmission line, the terminating resistor is selected such that the near field coupler operates as one or more unmatched transmission lines; and

a switching element electrically connected to the plurality of radiating elements adjacent to the first end of the dielectric substrate, wherein the switching element is provided in electrical communication with the transceiver and configured to selectively deactivate one or more radiating elements among the plurality of radiating elements by decoupling from the one or more radiating elements such that a near field effect is produced by the near field coupler in an operating region, the near field effect moving within the operating region and following the advancement of a targeted transponder.

2. The near field coupler according to claim 1 , wherein the switching element is comprised of a plurality of switches and wherein the number of switches is equal to or less than the number of radiating elements.

3. The near field coupler according to claim 2 , wherein at least one of the plurality of switches is a PIN diode.

4. The near field coupler according to claim 1 , wherein the plurality of radiating elements includes three radiating elements and each radiating element is a conductive strip disposed on the first surface of the dielectric substrate.

5. The near field coupler according to claim 1 , wherein the plurality of radiating elements are parallel to each other.

6. The near field coupler according to claim 1 , wherein the plurality of radiating elements are in a zig-zag configuration.

7. A near field coupler system adapted to provide selective communication between a transceiver and a targeted transponder disposed among multiple adjacent transponders, the near field coupler system comprising:

a transceiver configured to transmit communication signals;

a near field coupler structured to receive the communication signals from the transceiver and further configured to broadcast electromagnetic signals as a near field effect into at least a portion of a transponder operating region, the near field coupler comprising:

a plurality of radiating elements, and

a switching element electrically connected to the plurality of radiating elements and the transceiver, wherein the switching element is configured to selectively deactivate one or more of the radiating elements among the plurality of radiating elements, by decoupling from the one or more of the radiating elements, to adjust a pattern of the near field effect in the transponder operating region;

a transponder conveyance configured to advance at least one transponder on a path through the transponder operating region; and

a controller configured to control the near field coupler such that the pattern of the near field effect follows the advancement of the at least one transponder within the transponder operating region by operating the switching element based on at least one of an orientation and a location of the transponder within the transponder operating region.

8. The near field coupler system according to claim 7 , wherein the switching element is comprised of a plurality of switches and wherein the number of switches is equal to or less than the number of radiating elements.

9. The near field coupler system according to claim 7 , further comprising a printhead configured to print indicia upon the at least one transponder.

10. The near field coupler system according to claim 7 , wherein the near field coupler further includes a dielectric substrate and each of the radiating elements comprised of a conductive strip disposed on the dielectric substrate.

11. The near field coupler system according to claim 10 , wherein the conductive strips are parallel to each other.

12. The near field coupler system according to claim 11 , wherein the conductive strips are in a zig-zag configuration.

13. A method of communicating with a targeted transponder, the method comprising:

advancing the targeted transponder along a path;

generating a communication signal to a near field coupler having a plurality of radiating elements and a switching element for selectively deactivating at least one of the radiating elements by decoupling from the at least one of the radiating elements;

emanating, into at least a portion of a transponder operating region, a near field effect from a combination of activated radiating elements in the proximity of the targeted transponder in order to communicate with the targeted transponder; and

following the advancement of the targeted transponder with the near field effect, the near field effect moving within the transponder operating region by changing the combination of activated radiating elements via operation of the switching element based on at least one of an orientation and a location of the targeted transponder within the transponder operating region.

14. The method according to claim 13 , wherein at least one of the combinations of activated radiating elements includes one activated radiating element.