Ultra-remote LC Sensor Based on The Broken PT-Symmetry

Abstract

Inductor-capacitor (LC) passive wireless sensors have been widely used for continuous real-time detection in harsh or sealed environments where physical access is difficult. For implanted medical devices or sealed package applications, however, geometrical constraints such as small and non-invasive coils reduce the inductive coupling, turning the remote distance into a fundamental challenge. Here, we propose a new simple RLC passive readout circuit without the negative resistor which provides significant improvement of detection distance. We demonstrate both theoretically and experimentally the whole telemetry system breaking the Hermiticity while obeying the parity-time (PT)-symmetry and detect the signal in the broken PT- symmetric phase to avoid frequency splitting. Experimental results display that the readout distance of PT-symmetric system can be 4 times as long as conventional one, with parameters set in this paper.