FEM Analysis of Response Mechanism for Temperature Sensors Based on Surface Acoustic Wave Resonators

The response mechanism for temperature sensors based on surface acoustic wave (SAW) resonators was analyzed by using the finite element method (FEM). Modeling the periodic electrodes on a piezoelectric substrate in COMSOL, the material parameters and the thermal expansion of the periodic structure at different temperatures were considered. By using the modal analysis and the harmonic frequency response analysis, the relative frequency change of the SAW temperature sensor was deduced. The numerical results of frequency-temperature behavior for Y+33°-X quartz and Y+36°-X quartz agree well with the reported experimental results, confirming the efficiency of the proposed theoretical analysis. The FEM analysis can provide an effective guide for the application of SAW temperature sensors.