FEM Study on the Effect of Metallic Interdigital Transducers on Surface Acoustic Wave(SAW) Velocity in SAW Devices

A. K. Namdeo, and H. B. Nemade
Department of Electronics and Electrical Engineering
Indian Institute of Technology Guwahati
Assam, India

In this paper, we present study on the mass loading effect of the interdigital transducer (IDT) on surface acoustic wave (SAW) velocity in SAW devices, using COMSOL Multiphysics.

We have simulated a one port SAW resonator made on YZ lithium niobate substrate and investigated the reduction of SAW velocity caused by the mass loading of aluminum IDT fabricated over the substrate, using finite element method by COMSOL Multiphysics. An Eigenfrequency analysis provided by COMSOL Multiphysics is useful in finding the true surface and bulk wave velocities in the absence of IDT.

It has been observed that in the presence of IDT, the surface wave velocity decreases, however, the bulk wave velocity is not affected. The surface plots of surface and bulk standing waves in the device with IDT and without IDT are shown.