Dynamic impedance matching method for ultrahigh frequency passive tag analog front end

Abstract

The invention relates to the technical field of circuits, in particular to a dynamic impedance matching method for an ultrahigh frequency passive tag analog front end, which comprises a dynamic impedance matching network and a radio frequency analog front end, and is characterized in that the dynamic impedance matching network is composed of an eight-frequency-division circuit, a counting circuit, a logical algorithm control unit and a dynamic impedance matching unit; the radio frequency analog front end comprises a rectification circuit and a voltage-controlled oscillation circuit. According to the invention, a differential structure which has strong anti-interference capability and is suitable for bipolar signal processing is used, the impedance matching problem of an antenna and a circuit caused by interference can be offset, and the matching impedance of the differential shunt capacitor bank is adjusted by using the frequency change of the voltage-controlled oscillation circuit detected by the counting circuit. The overall impedance of the tag circuit and the impedance of the antenna are matched, the radio frequency energy transmission reaches the highest efficiency, the logic algorithm control unit selects the optimal capacitance value based on the performance change of the dynamic impedance matching network, the radio frequency energy transmission loss can be reduced, and the performance of the dynamic impedance matching network can be optimized.

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