Simulation of Unidirectional Interdigital Transducers in SAW Devices using COMSOL Multiphysics

Surface acoustic wave (SAW) devices based on Rayleigh wave, shear wave, love wave, acoustic plate mode (APM) wave and flexural plate wave have been explored for sensors, actuators and telecommunication applications. An interdigital transducer (IDT) is a metallic comb-like structure fabricated over piezoelectric substrate. SAWs are generated over the substrate by applying electrical signal to the IDT. A unidirectional IDT (UDT) is a type of IDT where the propagation of SAW is restricted to one direction. In this paper we have modeled a floating electrode unidirectional IDT (FEUDT) using COMSOL Multiphysics. In this simulation YZ lithium niobate is chosen as the substrate with mass less electrodes. The frequency response analysis is performed and admittance of the FEUDT is evaluated. Further the simulation results can be extended to extract coupling of mode (COM) parameters, which are vital in designing SAW devices.