Antenna matching circuit
First Claim
Patent Images
1. A diode matching antenna circuit for a radio frequency identification tag, comprising:
- a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the diode detector circuit, the stub circuit structured to match the impedance of the diode detector circuit in combination with the antenna to maximize the performance of the diode detector circuit.
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Accused Products
Abstract
A matching circuit for use with radio frequency identification tag antennas configured for modulated backscatter, the circuit including a stub circuit coupled to a detector diode and an antenna and sized and shaped to match a predetermined frequency. The stub circuit is also designed to couple to the antenna such that a resulting phase is seen at the output, preferably 180° from that seen at the input. In addition, the stub circuit is structured to perform as an antenna, thus increasing the sensitivity of the overall circuit and maximizing efficiency and performance.
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Citations
37 Claims
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1. A diode matching antenna circuit for a radio frequency identification tag, comprising:
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a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the diode detector circuit, the stub circuit structured to match the impedance of the diode detector circuit in combination with the antenna to maximize the performance of the diode detector circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radio frequency identification tag, comprising:
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a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter, the antenna circuit comprising;
a detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the detector circuit, the stub circuit structured to match the impedance of the detector circuit in combination with the antenna to maximize the performance of the detector circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A radio frequency identification tag system, comprising:
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a transceiver configured to transmit and receive radio frequency signals; and
at least one radio frequency identification tag, comprising;
a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter, the antenna circuit comprising;
a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the diode detector circuit, the stub circuit structured to match the impedance of the diode detector circuit in combination with the antenna to maximize the performance of the diode detector circuit. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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30. A modulated backscatter antenna circuit for a radio frequency identification tag, the circuit comprising:
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means for detecting the radio frequency identification signals, the detecting means comprising an antenna means coupled to a first terminal of a diode means; and
a stub circuit means for matching the impedance of the diode means in combination with the antenna means to maximize the performance of the diode means, the stub circuit means coupled to a second terminal of the diode means.
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31. A radio frequency identification tag circuit, comprising:
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means for processing radio frequency signals; and
radio frequency signal detection means coupled to the processing means and configured for modulated backscatter, the detection means comprising;
means for detecting the radio frequency identification signals, the detecting means comprising an antenna means and a diode means coupled together; and
a stub circuit means coupled to a node between the diode means and the radio frequency processing means for matching the impedance of the diode means in combination with the antenna means to maximize the performance of the diode means.
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32. A diode matching antenna circuit, comprising:
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a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the diode detector circuit to match the impedance of the diode detector circuit in combination with the antenna to maximize performance of the diode detector circuit, the stub circuit structured to phase shift an output signal at the second terminal of the diode detector circuit with respect to an input signal at the first terminal of the diode detector circuit and to function as an antenna in combination with the diode detector circuit and the antenna.
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33. A diode matching antenna circuit, comprising:
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a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit comprising a length of conductor material having one end coupled to the second terminal of the diode detector circuit to match the impedance of the diode detector circuit in combination with the antenna to maximize performance of the diode detector circuit, the stub circuit structured to phase shift an output signal at the second terminal of the diode detector circuit with respect to an input signal at the first terminal of the diode detector circuit and to function as an antenna in combination with the diode detector circuit and the antenna.
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34. A radio frequency identification tag, comprising:
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a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter of the radio frequency identification signals, the antenna circuit comprising;
a detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the detector circuit to match the impedance of the detector circuit in combination with the antenna to maximize the performance of the detector circuit, the stub circuit structured to phase shift an output signal at the second terminal of the detector circuit with respect to an input signal at the first terminal of the detector circuit and to function as an antenna in combination with the detector circuit and the antenna circuit.
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35. A radio frequency identification tag, comprising:
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a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter of the radio frequency identification signals, the antenna circuit comprising;
a detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit comprising a length of conductive material having one end coupled to the second terminal of the detector circuit to match the impedance of the detector circuit in combination with the antenna to maximize the performance of the detector circuit, the stub circuit structured to phase shift an output signal at the second terminal of the detector circuit with respect to an input signal at the first terminal of the detector circuit and to function as an antenna in combination with the detector circuit and the antenna circuit.
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36. A radio frequency identification system, comprising:
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a transceiver configured to transmit and receive radio frequency signals; and
at least one radio frequency identification tag, comprising;
a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter, the antenna circuit comprising;
a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit coupled to the second terminal of the diode detector circuit, the stub circuit structured to match the impedance of the diode detector circuit in combination with the antenna to maximize the performance of the diode detector circuit, and to phase shift an output signal at the second terminal of the diode detector circuit with respect to an input signal at the first terminal of the diode detector circuit, and further to function as an antenna in combination with the diode detector circuit and the antenna.
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37. A radio frequency identification system, comprising:
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a transceiver configured to transmit and receive radio frequency signals; and
at least one radio frequency identification tag, comprising;
a circuit for processing radio frequency identification signals; and
an antenna circuit coupled to the processing circuit and configured for modulated backscatter, the antenna circuit comprising;
a diode detector circuit having a first terminal coupled to an antenna and a second terminal; and
a stub circuit comprising a length of conductive material having one end coupled to the second terminal of the diode detector circuit, the stub circuit structured to match the impedance of the diode detector circuit in combination with the antenna to maximize the performance of the diode detector circuit, and to phase shift an output signal at the second terminal of the diode detector circuit with respect to an input signal at the first terminal of the diode detector circuit, and further to function as an antenna in combination with the diode detector circuit and the antenna.
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Specification