FEM Simulation of Quartz Thickness Shear Mode Resonator for Gas Sensing Applications

The objective of this paper is to present simulation results of the Thickness Shear Mode (TSM) resonator based on quartz using finite element simulation method. 3D model of quartz resonator and simulations were completed using finite element method in CoventorWare software suite for design and simulation of MEMS devices. Different techniques for simulation of adsorption effect on selective layer were studied: influence of change in mass of the sensitive layer and influence of change in density of the sensitive layer. Analyses of resonant modes were performed for both cases and displacement profiles in selected modes were determined for the resonator under study. Impedance and phase characteristics were calculated and measured for clean sample and sample with selective layer coated. The adsorption model calculates the frequency shift in basic resonant frequency with adsorbed amount of sensed gas. The simulation results were used in design of gas sensors for dangerous substances detection.