Method and system to determine physical parameters as between an RFID tag and a reader
First Claim
1. A method implemented in a radio frequency identification (RFID) system, the method comprising:
- an RFID reader generating an antenna feed signal and transmitting a first electromagnetic wave to an RFID tag according to the antenna feed signal;
the RFID reader receiving a backscattered electromagnetic wave from the RFID tag to create a received signal;
generating a combined signal based on the antenna feed signal and the received signal, wherein the combined signal includes a plurality of inflection points, each inflection point corresponding to a different position of the RFID tag relative to the RFID reader, wherein the plurality of inflection points comprises a first inflection point, a last inflection point, and at least one intermediate inflection point between the first inflection point and the last inflection point; and
determining a relative velocity between the RFID tag and the RFID reader by detecting the inflection points of the combined signal over a predetermined time period, wherein the predetermined time period begins at a time associated with the first inflection point and ends at a time associated with the last inflection point.
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Accused Products
Abstract
A method and system to determine physical parameters as between an RFID tag and a reader. At least some of the illustrative embodiments are methods comprising generating an antenna feed signal, and transmitting a first electromagnetic wave to a radio frequency device (by coupling the antenna feed signal to a reading antenna), receiving a backscattered electromagnetic wave from the radio frequency device to create a received signal, calculating a combined signal based on the antenna feed signal and received signal, and determining relative velocity between the radio frequency device and the reading antenna based on the combined signal.
48 Citations
17 Claims
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1. A method implemented in a radio frequency identification (RFID) system, the method comprising:
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an RFID reader generating an antenna feed signal and transmitting a first electromagnetic wave to an RFID tag according to the antenna feed signal; the RFID reader receiving a backscattered electromagnetic wave from the RFID tag to create a received signal; generating a combined signal based on the antenna feed signal and the received signal, wherein the combined signal includes a plurality of inflection points, each inflection point corresponding to a different position of the RFID tag relative to the RFID reader, wherein the plurality of inflection points comprises a first inflection point, a last inflection point, and at least one intermediate inflection point between the first inflection point and the last inflection point; and determining a relative velocity between the RFID tag and the RFID reader by detecting the inflection points of the combined signal over a predetermined time period, wherein the predetermined time period begins at a time associated with the first inflection point and ends at a time associated with the last inflection point. - View Dependent Claims (2, 3, 4, 5, 6, 17)
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7. A system comprising:
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a radio frequency identification (RFID) tag; a reading antenna; and a reader circuit coupled to the reading antenna to transmit a first electromagnetic wave to the RFID tag, based on an antenna feed signal, and to receive a received signal based on a backscattered electromagnetic wave from the RFID tag;
wherein the reader circuit generates a combined signal of the antenna feed signal and the received signal;wherein the combined signal includes a plurality of inflection points, each inflection point corresponding to a different position of the RFID tag relative to the reading antenna; wherein the plurality of inflection points comprises a first inflection point, a last inflection point, and at least one intermediate inflection point between the first inflection point and the last inflection point; wherein the reader circuit determines a relative velocity between the RFID tag and the reading antenna by detecting the inflection points of the combined signal over a predetermined time period, wherein the predetermined time period begins at a time associated with the first inflection point and ends at a time associated with the last inflection point. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A radio frequency identification (RFID) reader, comprising:
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a reading antenna; and a reader circuit coupled to the reading antenna to receive a backscattered electromagnetic wave from an RFID tag to create a received signal, wherein the reader circuit generates an antenna feed signal corresponding to the backscattered electromagnetic wave, the reader circuit determining a relative velocity between the RFID tag and the reader circuit based on a combined signal of the antenna feed signal and the received signal, wherein the combined signal includes a plurality of inflection points, each inflection point corresponding to a different position of the RFID tag relative to the reading antenna, wherein the plurality of inflection points comprises a first inflection point, a last inflection point, and at least one intermediate inflection point between the first inflection point and the last inflection point, wherein the reader circuit determines the relative velocity by detecting the inflection points of the combined signal over a predetermined time period, wherein the predetermined time period begins at a time associated with the first inflection point and ends at a time associated with the last inflection point. - View Dependent Claims (14, 15)
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16. A non-transitory computer-readable medium storing a program that, when executed by a radio frequency identification (RFID) system, causes the system to:
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generate an antenna feed signal and transmit a first electromagnetic wave from an RFID reader to an RFID tag according to the antenna feed signal; receive a backscattered electromagnetic wave from the RFID tag to create a received signal; generate a combined signal based on the antenna feed signal and the received signal, wherein the combined signal includes a plurality of inflection points, each inflection point corresponding to a different position of the RFID tag relative to the RFID reader, wherein the plurality of inflection points comprises a first inflection point, a last inflection point, and at least one intermediate inflection point between the first inflection point and the last inflection point; and determine a relative velocity between the RFID tag and the RFID reader by detecting the inflection points of the combined signal over a predetermined time period, wherein the predetermined time period begins at a time associated with the first inflection point and ends at a time associated with the last inflection point.
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Specification