FEM Simulation of Generation of Bulk Acoustic Waves and Their Effects in SAW Devices

This paper presents finite element method (FEM) simulation study of the generation of bulk acoustic waves (BAWs) and their effect on the performance of surface acoustic wave (SAW) devices, using COMSOL MultiphysicsTM. A SAW delay line structure using YZ-cut lithium niobate substrate is simulated. The radiation of the bulk waves in all angles into the interior of the substrate is analyzed. The bulk acoustic waves in SAW devices can affect the device response. Since BAW reflects from the bottom surface of the substrate and interferes with the received SAW at the output, bulk radiation needs careful consideration in the design of SAW devices.