RFID system with distributed read structure
First Claim
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, andwherein 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 andwherein 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.
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Accused Products
Abstract
A radio frequency identification (RFID) system includes a portable RFID reader, and a read infrastructure that includes a distributed read structure, which may be part of a display (such as a shelf) for holding objects. The read structure is used to couple the RFID reader to RFID devices (tabs and/or labels) on or near the structure. The RFID reader and the read structure communicate in a near field or proximity region communication, without any use of a direct ohmic electrical connection. The RFID reader may have an antenna that is configured for near field or proximity communication with a coupler of the read infrastructure. The RFID reader may also have a separate antenna for use in far field communication. The RFID reader may be able to obtain information more efficiently in the near field or proximity mode, allowing information to be received faster and with greater reliability.
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Citations
17 Claims
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1. A system for reading radio frequency identification (RFID) devices, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of reading radio frequency identification (RFID) devices, the method comprising:
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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. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of taking inventory, the method comprising:
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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.
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17. A point of sale system, comprising:
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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.
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Specification