Systems and methods to selectively connect antennas to receive and backscatter radio frequency signals
First Claim
1. A radio frequency identification (RFID) device, comprising:
- a plurality of antennas;
a plurality of diodes coupled to the plurality of antennas respectively;
a receiver coupled to the plurality of diodes, wherein when forward biased each of the plurality of diodes provides a path for radio frequency signals from a respective one of the plurality of antennas to reach the receiver; and
at least one controller coupled to the plurality of diodes to forward bias at least one of the diodes in a receiving mode and to change a backscatter state of at least one of the antennas to transmit data in a transmitting mode.
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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
26 Claims
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1. A radio frequency identification (RFID) device, comprising:
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a plurality of antennas; a plurality of diodes coupled to the plurality of antennas respectively; a receiver coupled to the plurality of diodes, wherein when forward biased each of the plurality of diodes provides a path for radio frequency signals from a respective one of the plurality of antennas to reach the receiver; and at least one controller coupled to the plurality of diodes to forward bias at least one of the diodes in a receiving mode and to change a backscatter state of at least one of the antennas to transmit data in a transmitting mode. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A radio frequency identification (RFID) device, comprising:
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a receiver; a plurality of antennas; a plurality of diodes, each of the plurality of diodes coupled between the receiver and a respective one of the plurality of antennas; and at least one controllers coupled to the plurality of diodes to selectively forward bias one or more of the diodes to allow radio frequency signals received via respective one or more of the antennas to reach the receiver, and selectively ground one or more of the antennas to transmit data. - 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 coupled to the diode to selectively bias the diode in one of a plurality of discrete states, including a first state to forward bias the diode and a second state to reverse bias the diode, wherein when forward biased the diode provides a path for radio frequency signals received by the antenna to reach the receiver, wherein when reverse biased the diode prevents radio frequency signals received by the antenna from reaching the receiver, and wherein the controllable circuit is configured to use the first state in receiving signals via the antenna and use the plurality of states in transmitting data via the antenna. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. 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 coupled to the diode to selectively forward bias the diode and reverse bias the diode, wherein the controllable circuit is further configured to selectively connect the antenna to ground and disconnect the antenna from the ground to transmit data via the antenna; wherein, when forward biased, the diode provides a path for radio frequency signals received by the antenna to reach the receiver, and wherein, when reverse biased, the diode prevents radio frequency signals received by the antenna from reaching the receiver. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification