Multi-element RFID coupler

• US 20070099566A1
• Filed: 10/31/2005
• Published: 05/03/2007
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: ZIH Corp. (Zebra Technologies Corporation)
• Inventors: Torchalski, Karl, Donato, Daniel, Borisov, Yevgeniy
• Granted Patent: US 8,078,103 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 13/206 Microstrip transmission line antennas
• CPC Class Codes: H04B 5/77 for interrogation

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.

Claims

1. A near field coupler structured in electrical communication with a transceiver for transmitting signals to a targeted transponder, the 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 the plurality of radiating elements are connected to the ground plane through the terminating resistor, 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 adapted to selectively activate one or more radiating elements among the plurality of radiating elements.

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 substantially 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 adapted to transmit communication signals;

a near field coupler structured to receive the communication signals from the transceiver and further adapted to broadcast electromagnetic signals into 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 adapted to selectively activate one or more of the radiating elements among the plurality of radiating elements to broadcast the electromagnetic signals into the transponder operating region; and

a transponder conveyance adapted to position at least one 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, further comprising a controller for regulating the switches based on the location of the targeted transponder in the transponder operating region.

11. 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.

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

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

14. A method of tuning a near field coupler system comprising the steps of:

transmitting a communication signal from a transceiver to a near field coupler, the near field coupler comprising a plurality of radiating elements and a switching element, wherein the switching element is adapted to provide selective electrical communication between the transceiver and one or more of the radiating elements among the plurality of radiating elements to define multiple radiating sets;

positioning a transponder arranged in an unknown orientation within a transponder operation region;

broadcasting an electromagnetic signal into the transponder operating region based upon the selective communication facilitated by the switching element between the transceiver and the plurality of radiating elements;

determining a power level for each of the multiple radiating sets that accommodates a reliable encoding process between the transceiver and the transponder; and

determining a lowest power level among the power levels for each of the multiple radiating sets that accommodates the reliable encoding process for purposes of fixing a preferred radiating set for interrogating subsequent transponders arranged in the unknown orientation.

15. The method according to claim 14, further comprising storing the preferred radiating set for subsequent transponders arranged in the unknown orientation.

16. 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 activating at least one of the radiating elements such that each activated radiating element receives the signal;

emanating 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 by changing the combination of activated radiating elements.

17. The method according to claim 16, wherein at least one of the combinations of activated radiating elements includes one activated radiating element.