Acoustic network analysis and equivalent circuit simulation of the thickness-shear mode acoustic wave sensor in the liquid phase

Abstract

Network analysis of the behavior of the thickness-shear mode (TSM) acoustic wave sensor is validated and the ability of the Butterworth—Van Dyke (BVD) equivaleny circuit to describe the electrical characteristics of the sensor was examined under various conditions. The results demonstrate that the impedance of the quartz crystal can be measured when one or both sides of the device are immersed in a viscous liquid or a conductive solution. The equivalent circuit is satisfactory in simulating the impedance characteristics of the TSM sensor in the liquid phase under most conditions except for total immersion of the sensor in highly viscous or conductive liquids. It is shown that the frequency response of the TSM device depends on individual crystals and experimental configurations.