RFID system with distributed read structure

1. A system for reading radio frequency identification (RFID) devices, comprising:

a distributed read structure coupled to a read structure coupler for proximity coupling with RFID devices within one wavelength of radiation emitted by the read structure;

the read structure coupler including one of i) a central active patch or plane of conductive material flanked by a pair of outer ground patches or planes of conductive material or ii) a microstrip or other transmission line; and

wherein an RFID reader having an antenna, in a near field mode of operation, can couple with the RFID device through the read structure coupler and the read structure, and

wherein the RFID reader, in a far field mode of operation, can couple with the RFID device independent of the read structure coupler and the read structure such that the RFID reader utilizes the antenna for both the near field and far field mode,

wherein the RFID reader selects between the near field mode of operation and the far field mode of operation by periodically transmitting in each mode of operation and selecting the mode of operation with the lowest return loss and if the antenna, when utilized in far field mode, has a return loss that exceeds a fixed level, the RFID reader may select the near field mode of operation and

wherein communication between the RFID reader and the read structures involves communicating information on all RFID devices in a single coupling between the RFID reader and the read structure.

2. The system of claim 1 , further comprises a display device.

3. The system of claim 2 , wherein the display device further includes a shelf with at least part of the distributed read structure thereupon.

4. The system of claim 3 , wherein at least some of the RFID devices are attached to respective objects that are on or in the display device.

5. The system of claim 1 , wherein the RFID reader includes:

electronics coupled to the antenna; and

wherein the electronics include electronics for operating the RFID reader in two separate modes:

the near field mode in which the RFID reader communicates by proximity coupling; and

wherein the RFID reader communicates in the far field mode by far field coupling.

6. The system of claim 1 , wherein the antenna is a patch antenna.

7. The system of claim 1 , wherein the RFID reader is a portable RFID reader.

8. The system of claim 1 , wherein the read structure further includes conductive patterns that generate electrical fields between the conductive patterns for proximity communication with the RFID devices.

9. The system of claim 1 , wherein the read structure coupler further includes multiple conductive plates.

10. A method of reading radio frequency identification (RFID) devices, the method comprising:

operatively coupling the RFID devices to a distributed read structure of a read infrastructure in which the read infrastructure includes an amplifier;

operatively coupling an RFID reader to a coupler of the read infrastructure;

reading the RFID devices through an antenna of the RFID reader wherein the RFID reader, in a near field mode of operation, can couple with the RFID device through the coupler and the read structure, and the RFID reader, in a far field mode of operation, can couple with the RFID device independent of the coupler and the read structure such that the RFID reader utilizes the antenna for both the near field and far field mode; and

wherein the RFID reader selects between the near field mode of operation and the far field mode of operation by periodically transmitting in each mode of operation and selecting the mode of operation with the lowest return loss, and if the antenna of the RFID reader, when utilized in far field mode, has a return loss that exceeds a fixed level, the RFID reader may select the near field mode of operation;

wherein communication between the RFID reader and the read structures involves communicating information on all RFID devices in a single coupling between the RFID reader and the read structure.

11. The method of claim 10 , wherein the operative coupling between the RFID devices and the distributed read structure is proximity coupling.

12. The method of claim 10 , wherein the operative coupling between the RFID reader and the coupler is proximity coupling.

13. The method of claim 10 ,

wherein the RFID reader is a portable RFID reader; and

wherein the operatively coupling the RFID reader to the coupler includes moving the antenna of the RFID reader into proximity coupling with the coupler.

14. The method of claim 10 ,

wherein the near field mode differs from the far field mode of the RFID reader in one or more of frequency of communication, power utilized, and communication protocol.

15. The method of claim 10 ,

wherein the read infrastructure further comprises a display device; and

wherein the RFID devices are mechanically attached to respective objects that are on or in the display device.

16. A method of taking inventory, the method comprising:

providing objects with RFID devices in or on a display device having a read infrastructure;

placing a dual antenna of an RFID reader in proximity coupling with a coupler of the read infrastructure; and

initiating communication between the RFID reader and the RFID devices, through the coupler and through a distributed read structure of the read infrastructure wherein the RFID reader, in a near field mode of operation, can couple with the RFID device through the coupler and the read structure, and wherein the RFID reader, in a far field mode of operation, can couple with the RFID device independent of the coupler and the read structure such that the RFID reader utilizes the dual antenna for both the near field and far field mode; and

wherein the RFID reader selects between the near field mode of operation and the far field mode of operation by periodically transmitting in each mode of operation and selecting the mode of operation with the lowest return loss and if the dual antenna of the RFID reader, when utilized in far field mode, has a return loss that exceeds a fixed level, the RFID reader may select the near field mode of operation;

wherein communication between the RFID reader and the read structures involves communicating information on all RFID devices in a single coupling between the RFID reader and the read structure.

17. A point of sale system, comprising:

a display having a plurality of objects disposed thereon, with each of the objects having an RFID device attached thereto; and

a read structure connected to a read structure coupler for operating in two separate modes;

wherein the RFID devices are read through one of the two separate modes and wherein an antenna of an RFID reader, in a near field mode of operation, can couple with the RFID device through the coupler and the read structure, and wherein the antenna of the RFID reader, in a far field mode of operation, can couple with the RFID device independent of the coupler and the read structure such that the RFID reader includes reader electronics and the RFID reader utilizes the antenna for both the near field and far field mode; and

wherein the RFID reader selects between the near field mode of operation and the far field mode of operation by periodically transmitting in each mode of operation and selecting the mode of operation with the lowest return loss and if the antenna of the RFID reader, when utilized in far field mode, has a return loss that exceeds a fixed level, the RFID reader may select the near field mode of operation;

wherein the RFID reader electronics communicate differently for near field and far field mode; and

wherein communication between the RFID reader and the read structures involves communicating information on all RFID devices in a single coupling between the RFID reader and the read structure.