Design of passive wireless interface module reactance sensor based on Surface Acoustic Wave

Based on Surface Acoustic Wave Resonator (SAWR), the SAWR equivalent circuit is built, and its model is established, so the circuit parameters of SAWR are obtained by S11 of Vector Network Analyzer (VNA). Furthermore, taking the T type for example, the values of interface matching element are calculated based on self-adaptation matching theory. The processes of actual matching verify the validity of theoretical matching research, and finding the matching difference between the actual value and the calculation value. Then single ended interface module is designed, tested, wired and wireless analyzed, sensor analysis, the results of which show the validity of single ended interface module and give a scheme of Pi-CLC double ended interface module based on linearity and sensitivity. Finally, double ended interface module is also packaged, wired and wireless test proves the validity of it, the difference frequency analysis shows that reference resonator not affect the main resonator to dominant the difference frequency changing with capacitance sensor and SWR analysis shows the design validity of low mismatching network.