Continuous wave (CW)—fixed multiple frequency triggered, radio frequency identification (RFID) tag and system and method employing same
First Claim
1. A far field radio frequency identification (RFID) tag having an associated tag identification (ID) responsive to a group of a plurality of continuous wave (CW), unmodulated signals selected from frequencies comprising a predetermined frequency band, that correspond to the tag ID of the RFID tag.
1 Assignment
0 Petitions
Accused Products
Abstract
A far field radio frequency identification (RFID) tagging and tracking system employing a plurality of continuous wave (CW), unmodulated signals selected from frequencies including a predetermined frequency band, includes a RFID interrogator generating a group of CW unmodulated signals corresponding to a RFID tag and receiving a tag identification (ID) signal sequence uniquely identifying the RFID tag, while the RFID tag includes a power source supplying power to the RFID tag but not including a microprocessor. A corresponding RFID tag and method for operating both the tag and the system are also described.
92 Citations
32 Claims
- 1. A far field radio frequency identification (RFID) tag having an associated tag identification (ID) responsive to a group of a plurality of continuous wave (CW), unmodulated signals selected from frequencies comprising a predetermined frequency band, that correspond to the tag ID of the RFID tag.
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3. A far field radio frequency identification (RFID tag responsive to a plurality of continuous wave (CW), unmodulated signals selected from frequencies including a predetermined frequency band, the RFID tag comprising:
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an antenna generating received CW signals responsive to the CW unmodulated signals; a filter bank generating noise-free CW signals responsive to the received CW signals; a rectifier bank generating a binary word responsive to the noise-reduced CW signals; a logic circuit generating a command signal when the received binary word corresponds to a tag identifier code programmed into the logic circuit; and a state machine coupled to the antenna and responsive to the command signal generating information identifying the RFID tag for transmission via the antenna. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A method of operating a far field radio frequency identification (RFID) tag responsive to a plurality of continuous wave (CW), unmodulated signals selected from frequencies comprising a predetermined frequency band, comprising:
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receiving the plurality of CW unmodulated signals; determining whether a binary word indicated by the received plurality of CW unmodulated signals taken together as a group of frequency matches; a tag identifier for the RFID tag programmed into a logic circuit; and outputting information distinguishing the RFID tag from similar RFID tags when the binary word matches the tag identifier. - View Dependent Claims (10, 11)
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- 12. A far field radio frequency identification (RFID) tagging and tracking system employing a plurality of continuous wave (CW), unmodulated signals selected from frequencies comprising a predetermined frequency band, the system including a RFID interrogator generating a group of CW unmodulated signals, the group of frequencies as a whole corresponding to a RFID tag and receiving a tag identification (ID) signal sequence uniquely identifying the RFID tag.
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14. A far field radio frequency identification (RFID) tagging and tracking system employing a plurality of continuous wave (CW), unmodulated signals selected from frequencies comprising a predetermined frequency band, the system including an RFID interrogator generating a group of CW unmodulated signals corresponding to an RFID tag and receiving a tag identification (ID) signal sequence uniquely identifying the RFID tag, wherein:
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the RFID interrogator comprises; first and second antennas; a front end coupled to the first antenna that extracts the tag ID signal sequence from a received signal; a controller receiving the tag ID signal sequence and generating control signals; a multiple frequency generator generating a plurality of CW unmodulated frequency signals; a switch array responsive to the control signals that route selected ones of the CW unmodulated frequency signals to a frequency summer; and the frequency summer, which applies the selected ones of the CW unmodulated frequency signals to the second antenna; and the RFID tag comprises; a third antenna generating received CW signals responsive to the selected ones of the CW unmodulated frequency signals output by the second antenna; a filter bank generating noise-free CW signals responsive to the received CW signals; a rectifier bank generating a binary word responsive to the noise-reduced CW signals; a logic circuit generating a command signal when the received binary word corresponds to a tag identifier code programmed into the logic circuit; and a state machine coupled to the third antenna and responsive to the command signal generating the tag ID signal sequence for transmission via the third antenna to the RFID interrogator. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for operating a far field radio frequency identification (RFID) tagging and tracking system responsive to a plurality of continuous wave (CW), unmodulated frequency signals selected from frequencies comprising a predetermined frequency band, wherein a RFID interrogator includes a multiple frequency generator producing the frequencies included in the predetermined frequency band, a controller, a switch array operated by the controller, and a frequency summer for combining the CW unmodulated frequency signals output by the switch array, while a RFID tag includes an antenna, a filter bank, a rectifier bank, a logic circuit, and a state machine, electrically coupled to one another in the recited order, the state machine being coupled to a RFID tag antenna, a power source supplying power to the RFID tag, comprising:
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transmitting CW unmodulated frequency signals corresponding to a binary word; extracting the binary word from the CW unmodulated frequency signals; comparing the binary word to a tag identifier for the RFID tag programmed into the logic circuit; and when the binary word matches the tag identifier, controlling the state machine to output a tag identification (ID) signal sequence distinguishing the RFID tag from similar RFID tags. - View Dependent Claims (24)
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25. A far field radio frequency identification (RFID) tag having a binary identification, the tag comprising:
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an antenna to receive a plurality of different, unmodulated, continuous wave (CW) electromagnetic frequencies from an interrogator; a first circuit to provide an indication that the plurality of received CW frequencies together as a group of frequencies correspond to the binary identification; and a second circuit to send a message to the interrogator in response to the indication. - View Dependent Claims (26, 27, 28)
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29. A far field radio frequency identification (RFID) system comprising:
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an interrogator to transmit a plurality of different, unmodulated, continuous wave (CW) electromagnetic frequencies wherein the plurality of unmodulated CW frequencies as a group of signals correspond to a binary identification; and an RFID tag corresponding to the binary identification to receive the plurality of different unmodulated, continuous wave (CW) electromagnetic frequencies and to transmit a message to the interrogator in response to the received frequencies. - View Dependent Claims (30, 31, 32)
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Specification