RFID radio frequency identification or property monitoring method and associated apparatus
First Claim
1. A method of identifying an article of interest, comprising:
- providing one of a plurality of RF antennas each having a non-linear element and being resonant at one of a plurality of different frequencies positioned on an article of interest,interrogating said one RF antenna with RF energy of a first frequency,converting said interrogating RF energy into reflected RF energy of a different frequency from said first frequency,sensing said reflected RF energy,determining a difference between said first frequency and said different frequency by subtracting one of said first frequency and said different frequency from the other of said first frequency and said different frequency, andon the basis of said difference between said first frequency and said different frequency determining if a specific said antenna is present.
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Accused Products
Abstract
A method of identifying an article of interest includes providing one of a plurality of RF antennas each having a non-linear element which may be a rectifying diode and being resident at a different frequency on the article of interest. One RF antenna is interrogated with RF energy of a first frequency and converts the interrogated RF energy into a reflected energy of a different frequency. The reflected energy is sensed and on the basis of the different frequency determining if a specific antenna is present. The non-linear element may be a diode and is preferably a variable non-linear element. In another embodiment, the reflected RF energy is responsive to a change in ambient physical conditions such as pressure or temperature. Corresponding apparatus is provided.
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Citations
41 Claims
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1. A method of identifying an article of interest, comprising:
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providing one of a plurality of RF antennas each having a non-linear element and being resonant at one of a plurality of different frequencies positioned on an article of interest, interrogating said one RF antenna with RF energy of a first frequency, converting said interrogating RF energy into reflected RF energy of a different frequency from said first frequency, sensing said reflected RF energy, determining a difference between said first frequency and said different frequency by subtracting one of said first frequency and said different frequency from the other of said first frequency and said different frequency, and on the basis of said difference between said first frequency and said different frequency determining if a specific said antenna is present. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Apparatus for determining if an article of interest is present, comprising:
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said article of interest having at least one antenna, one of said at least one antenna being resonant at one frequency of a plurality of available frequencies, a non-linear element operatively associated with said one of said at least one antenna, an RF frequency generator for directing RF energy of a particular frequency to said one of said at least one antenna, said non-linear element causing said one of said at least one antenna to transmit reflected RF energy in response to receipt of said RF energy, said reflected RF energy having a reflected frequency that is different than said directed particular frequency, a detector for receiving said reflected RF energy from said one of said at least one antenna, and a processor adapted to determine a difference between said directed particular frequency and said reflected frequency by subtracting one of said directed particular frequency and said reflected frequency from the other of said directed particular frequency and said reflected frequency and to determine from a said difference between said reflected frequency and said directed particular frequency whether the one of said at least one antenna is a specific antenna. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of monitoring an ambient physical property, comprising:
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providing an antenna having a non-linear element whose response depends on the physical property being monitored, interrogating said RF antenna with RF energy of a first frequency, converting the interrogating RF energy into reflected RF energy of a different frequency from said first frequency, said different frequency being dependent on the physical property being monitored, sensing said reflected RF energy, determining a difference between said first frequency and said different frequency by subtracting one of said first frequency and said different frequency from the other of said first frequency and said different frequency, and on the basis of said difference between said first frequency and said different frequency determining the state of said physical property. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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33. Apparatus for monitoring an ambient physical property, comprising:
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an antenna being resonant at one frequency of a plurality of available frequencies, a non-linear element operatively associated with said antenna whose response depends on the physical property being monitored, an RF frequency generator for directing RF energy at a particular frequency to said antenna, said non-linear element causing said antenna to transmit reflected RF energy in response to receipt of said RF energy, said reflected RF energy having a reflected frequency that is different than said directed particular frequency and that is dependent on the physical property being monitored, a detector for receiving said reflected RF energy from said antenna, and a processor adapted to determine a difference between said particular frequency and said reflected frequency by subtracting one of said particular frequency and said reflected frequency from the other of said particular frequency and said reflected frequency and to determine from a said difference between said particular frequency and said reflected frequency the state of the physical property being monitored. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41)
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Specification