Passive sensor tag system
First Claim
1. A passive sensor tag system, comprising:
- a passive electronic sensor tag having a sensor element and a sensor circuit, the sensor element configured to sense a change in a local environmental variable and to alter a fundamental electrical resonance frequency characteristic of the sensor circuit as a result of the change in the local environmental variable, wherein the local environmental variable is one of light, temperature, pressure, vibration, stress, and strain;
an external readout including an external readout circuit configured to generate a signal having a frequency and a voltage and to transmit the signal through an output antenna to the passive electronic sensor tag, wherein the external readout circuit includes a first analog-to-digital converter (ADC) sampling the signal before the output antenna and a second ADC sampling the signal after the output antenna, the external readout determining the impedance of the coupled system based on the sampling of the first ADC and the second ADC, the transmitted signal coupling the sensor circuit and the external readout circuit, the external readout determining the fundamental electrical resonance frequency characteristic of the sensor circuit from a change in an impedance of the coupled sensor circuit and external readout circuit, the external readout determining the change in the local environmental variable from the alteration in the fundamental electrical resonance frequency characteristic of the sensor circuit, wherein the fundamental electrical resonance frequency characteristic is one of a fundamental electrical resonance frequency of the sensor circuit, a width of a resonance frequency response trough, a width of a resonance frequency response crest, and quality factor of the resonance.
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Abstract
A passive sensor tag system including a passive electronic sensor tag and an external readout. The passive electronic sensor tag including a sensor element configured to sense data in a local environment and to cause a shift in a fundamental electrical resonance frequency characteristic of a sensor circuit based on the sensed data. The external readout including an external readout circuit that is configured to generate a signal having a frequency and a voltage and to transmit the signal through an output antenna. The transmitted signal coupling the sensor circuit and the external readout circuit. The external readout determining a fundamental electrical resonance frequency characteristic of the sensor circuit based on the impedance of the coupled sensor circuit and external readout circuit. The external readout determining the sensed data based the fundamental electrical resonance frequency characteristic of the sensor circuit.
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Citations
11 Claims
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1. A passive sensor tag system, comprising:
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a passive electronic sensor tag having a sensor element and a sensor circuit, the sensor element configured to sense a change in a local environmental variable and to alter a fundamental electrical resonance frequency characteristic of the sensor circuit as a result of the change in the local environmental variable, wherein the local environmental variable is one of light, temperature, pressure, vibration, stress, and strain; an external readout including an external readout circuit configured to generate a signal having a frequency and a voltage and to transmit the signal through an output antenna to the passive electronic sensor tag, wherein the external readout circuit includes a first analog-to-digital converter (ADC) sampling the signal before the output antenna and a second ADC sampling the signal after the output antenna, the external readout determining the impedance of the coupled system based on the sampling of the first ADC and the second ADC, the transmitted signal coupling the sensor circuit and the external readout circuit, the external readout determining the fundamental electrical resonance frequency characteristic of the sensor circuit from a change in an impedance of the coupled sensor circuit and external readout circuit, the external readout determining the change in the local environmental variable from the alteration in the fundamental electrical resonance frequency characteristic of the sensor circuit, wherein the fundamental electrical resonance frequency characteristic is one of a fundamental electrical resonance frequency of the sensor circuit, a width of a resonance frequency response trough, a width of a resonance frequency response crest, and quality factor of the resonance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification