3D Modeling and Simulation of SH-SAW Devices Using the Finite Element Method

Shear horizontal surface acoustic wave (SH-SAW) devices have been extensively used in chemical and biosensing applications mainly because these waves are not attenuated in liquid media like Rayleigh waves. It is extremely important to model and simulate the device prior to its actual fabrication in order to gain a better understanding of the device performance and optimizing its design parameters. This paper presents the 3-dimensional finite element (FE) modeling and simulation results for a SH-SAW device using CoventorWaretrade (CW). The substrate used is 64deg rotated Y-cut LiNbO₃ with Au/Cr Interdigital Transducers (IDT) having a periodicity of 40 mum. 3D transient analysis was performed on the devices to study the acoustic wave propagation and characterize the device in time and frequency domain. The normalized displacements at the output node are presented together with a 3D view of the SH-SA W wave propagation on the substrate. Also, a comparison is provided between the measured and simulated frequency response.