Systems and methods to selectively connect antennas to receive and backscatter radio frequency signals
First Claim
1. A radio frequency identification (RFID) tag, comprising:
- a plurality of antennas of different polarizations;
a plurality of diodes coupled to the plurality of antennas respectively;
a receiver coupled to the plurality of diodes to receive radio frequency signals from the antennas when the diodes are forward biased; and
a set of one or more current controllers coupled to the plurality of diodes;
wherein, in a receiving mode, the set of one or more current controllers is configured to forward bias at least one of the diodes to receive radio frequency signals from an RFID reader; and
wherein, in a transmitting mode, the set of one or more current controllers is configured to change a backscatter state of at least one of the antennas according to data to be transmitted from the RFID tag.
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Accused Products
Abstract
Systems and methods to selectively attach and control antennas via diodes and current sources. In one embodiment, a system includes: an RFID reader having a plurality of reader antennas of different polarizations to transmit radio frequency signals; and at least one RFID tag. The RFID tag includes: a plurality of tag antennas of different polarizations; a plurality of diodes coupled to the plurality of tag antennas respectively; a receiver coupled to the plurality of diodes to receive the radio frequency signals from the tag antennas when the diodes are forward biased; and a set of one or more current controllers coupled to the plurality of diodes. In a receiving mode the controllers selectively forward bias the diodes to receive the signals from the RFID reader. In a transmitting mode the controllers selectively change the state of the tag antennas to transmit data via backscattering the radio frequency signals.
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Citations
20 Claims
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1. A radio frequency identification (RFID) tag, comprising:
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a plurality of antennas of different polarizations; a plurality of diodes coupled to the plurality of antennas respectively; a receiver coupled to the plurality of diodes to receive radio frequency signals from the antennas when the diodes are forward biased; and a set of one or more current controllers coupled to the plurality of diodes; wherein, in a receiving mode, the set of one or more current controllers is configured to forward bias at least one of the diodes to receive radio frequency signals from an RFID reader; and wherein, in a transmitting mode, the set of one or more current controllers is configured to change a backscatter state of at least one of the antennas according to data to be transmitted from the RFID tag. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A radio frequency identification (RFID) tag, comprising:
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a receiver; a plurality of antennas; a plurality of diodes coupled between the plurality of antennas and the receiver; and a plurality of current controllers coupled to the plurality of diodes respectively; wherein the current controllers are configured to selectively forward bias one or more of the diodes to allow signals received via respective one or more of the antennas to reach the receiver; and wherein the current controllers are further configured to selectively ground one or more of the antennas to modulate backscatter. - View Dependent Claims (8, 9, 10, 11)
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12. A radio frequency device, comprising:
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an antenna; a receiver; a diode coupled between the antenna and the receiver; and a controllable circuit path coupled to the diode, wherein the circuit path is controlled in a first mode to provide a forward bias current to the diode and in a second mode to reverse bias the diode; wherein the forward bias current is configured to allow radio frequency signals received by the antenna to reach the receiver via the diode; and wherein when reverse biased, the diode is configured to prevent signals received by the antenna from reaching the receiver. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification