Device and method for selective backscattering of wireless communications signals
First Claim
1. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
- at least two antennas configured to receive carrier waves from the carrier wave source; and
an RFID circuit including a passive power supply circuit configured to rectify at least some of the carrier waves received via the at least two antennas to provide power to the RFID circuit, the RFID circuit configured to select which of the at least two antennas to employ for outgoing transmissions, if any, based at least in part on an indication of an amount of power being received at the RFID device via respective ones of the antennas, and the passive power supply circuit further configured to modulate at least some of the carrier waves received via the at least two antennas with information and backscatter the modulated carrier waves via the selected one or more of the antennas, if any, wherein the RFID circuit is configured to select for the outgoing transmissions the antenna of the at least two antennas that receives a lower of the amounts of power.
1 Assignment
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Accused Products
Abstract
A radio frequency identification (RFID) device with two or more antennas may select one antenna to backscatter or otherwise transmit, while deriving power from receipt of a carrier wave at one or more other antennas. The RFID device may select the antenna receiving the lower power or producing the lower voltage to transmit. The RFID device may select the antenna receiving the higher power or producing the higher voltage to transmit if the lower power or voltage is insufficient to operate the RFID device to backscatter or transmit. The RFID device may select neither antenna to transmit if the higher power or voltages are insufficient to operate the RFID device to backscatter or transmit.
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Citations
30 Claims
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1. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
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at least two antennas configured to receive carrier waves from the carrier wave source; and an RFID circuit including a passive power supply circuit configured to rectify at least some of the carrier waves received via the at least two antennas to provide power to the RFID circuit, the RFID circuit configured to select which of the at least two antennas to employ for outgoing transmissions, if any, based at least in part on an indication of an amount of power being received at the RFID device via respective ones of the antennas, and the passive power supply circuit further configured to modulate at least some of the carrier waves received via the at least two antennas with information and backscatter the modulated carrier waves via the selected one or more of the antennas, if any, wherein the RFID circuit is configured to select for the outgoing transmissions the antenna of the at least two antennas that receives a lower of the amounts of power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
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at least two antennas configured to receive carrier waves from the carrier wave source; and an RFID circuit including a passive power supply circuit configured to rectify at least some of the carrier waves received via the at least two antennas to provide power to the RFID circuit, the RFID circuit configured to select which of the at least two antennas to employ for outgoing transmissions, if any, based at least in part on an indication of an amount of power being received at the RFID device via respective ones of the antennas, and the passive power supply circuit further configured to modulate at least some of the carrier waves received via the at least two antennas with information and backscatter the modulated carrier waves via the selected one or more of the antennas, if any, wherein the RFID circuit comprises logic that is configured to compare an indication of a voltage being received via the respective antennas, and to select for outgoing transmissions, the antenna of the at least two antennas that receives a lower of the voltages.
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13. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
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at least two antennas configured to receive carrier waves from the carrier wave source; and an RFID circuit including a passive power supply circuit configured to rectify at least some of the carrier waves received via the at least two antennas to provide power to the RFID circuit, the RFID circuit configured to select which of the at least two antennas to employ for outgoing transmissions, if any, based at least in part on an indication of an amount of power being received at the RFID device via respective ones of the antennas, and the passive power supply circuit further configured to modulate at least some of the carrier waves received via the at least two antennas with information and backscatter the modulated carrier waves via the selected one or more of the antennas, if any, wherein the RFID circuit comprises logic that is configured to compare an indication of a voltage being received via the respective antennas from the carrier wave received from the carrier wave source, and to select for outgoing transmissions the antenna of the at least two antennas that generates a lower of the voltages if the generated voltage is at least equal to a minimum voltage, and to otherwise select for outgoing transmissions, the antenna of the at least two antennas that generates a higher of the voltages.
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14. A method of operating a radio frequency identification (RFID) device, the method comprising:
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receiving carrier waves at a first and a second antenna of the RFID device; rectifying the received carrier waves to power the RFID device; selecting which of at least the first and the second antennas to employ for outgoing transmissions, if any, based at least in part on a number of values indicative of an amount of power being received at the RFID device via respective ones of at least the first and the second antennas, wherein selecting which of the at least the first and the second antennas to employ for outgoing transmissions includes comparing the values indicative of the amount of power being received at the RFID device via the respective ones of the first and the second antennas, and selecting for outgoing transmissions, the antenna of the first and the second antennas that receives a lower of the amounts of power; and backscattering a modulated carrier wave from the RFID device via the selected one of at least the first and the second antennas, if any, the modulated carrier wave modulated with information stored in the RFID device. - View Dependent Claims (15, 16, 17)
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18. A method of operating a radio frequency identification (RFID) device, the method comprising:
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receiving carrier waves at a first and a second antenna of the RFID device; rectifying the received carrier waves to power the RFID device; selecting which of at least the first and the second antennas to employ for outgoing transmissions, if any, based at least in part on a number of values indicative of an amount of power being received at the RFID device via respective ones of at least the first and the second antennas, wherein selecting which of the at least the first and the second antennas to employ for outgoing transmissions includes comparing the values indicative of a voltage being supplied via the first and the second antennas from the carrier waves, and to select for outgoing transmissions an antenna of the first and the second antennas that supplies a lower of the voltages if the supplied voltage is at least equal to a minimum voltage, and to otherwise select for outgoing transmissions, the antenna of the first and the second antennas that supplies a higher of the voltages; and backscattering a modulated carrier wave from the RFID device via the selected one of at least the first and the second antennas, if any, the modulated carrier wave modulated with information stored in the RFID device. - View Dependent Claims (19, 20)
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21. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
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at least two antennas for receiving carrier waves from the carrier wave source; and means for modulating at least some of the carrier waves received via the at least two antennas with information, selecting which of the at least two antennas to employ for outgoing transmissions, if any, based on at least in part a number of values indicative of an amount of power being received at the RFID device via respective ones of the antennas, and backscattering the modulated carrier waves via the selected one or more of the antennas, if any, wherein the means for modulating at least some of the carrier waves is configured to compare the values indicative of the amount of power being received via the respective antennas, and to select for outgoing transmissions, the antenna of the at least two antennas that receives a lower of the amounts of power. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A radio frequency identification (RFID) device operable to derive power from a carrier wave source that is separate and distinct from the RFID device, the RFID device comprising:
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at least two antennas for receiving carrier waves from the carrier wave source; and means for modulating at least some of the carrier waves received via the at least two antennas with information, selecting which of the at least two antennas to employ for outgoing transmissions, if any, based on at least in part a number of values indicative of an amount of power being received at the RFID device via respective ones of the antennas, and backscattering the modulated carrier waves via the selected one or more of the antennas, if any, wherein the means for modulating at least some of the carrier waves is configured to compare the values indicative of a voltage being supplied via the respective antennas from the carrier wave received from the carrier wave source, and to select for outgoing transmissions the antenna of the at least two antennas that supplies a lower of the voltages if the supplied voltage is at least equal to a minimum voltage, and to otherwise select for outgoing transmissions, the antenna of the at least two antennas that supplies a higher of the voltages. - View Dependent Claims (30)
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Specification