Shear horizontal surface acoustic wave COMSOL modeling on lithium niobate piezoelectric substrate

Abstract

Shear horizontal surface acoustic wave (SHSAW), one type of the Surface Acoustic Wave is most suitable for the liquid based application as SHSAW has the advantage of acoustic energy is not being radiated into liquid. Hence, SHSAW device has the potential to provide high-performance sensing platform in pathogen sensing research. Since 1960, there have been a lot of complicated theoretical models for the SAW devices development, such as from delta function model, equivalent circuit model, coupling-of-modes (COM) model, P-matrix model and Computer Simulation Technology Studio Suite (CST), finite element analysis (FEA) model. Unfortunately, these models have been developed more toward telecommunication application such as signal filters and resonators. However, SHSAW device development in this research is not meant for signal filter or resonators but used for surface sensing purpose through mass loading effects detection, therefore COMSOL Multiphysics was used to modeling the SHSAW for pathogen sensing development. Three resonant frequencies of 15 μm, 20 μm and 25 μm width electrodes were simulated in this paper as preliminary evaluation of the applicable of COMSOL Multiphysics in SHSAW research. The comparison has shown that the difference between theoretical calculation and simulation result is less than 10%.