Patent ID: 8847764
Filing Date: 2014-09-30
Classification: G06K

Abstract:
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.