Semi-analytical finite element analysis of acceleration-induced frequency change in SAW resonators

A quantitative analysis tool has been developed which determines the acceleration induced frequency change for surface acoustic waves (SAW) traveling in an arbitrary piezoelectric crystal resonator. This analysis tool uses a finite element approach to solve the static bias problem and Sinha and Tiersten's analytical technique to determine the SAW mode shape. Combining this data with the spatially varying effective elastic constants, the numerical perturbation integral derived by Tiersten determines the acceleration sensitivity of the SAW resonator. The unique aspect of this software is the determination of the spatially varying effective elastic constants using finite element shape functions. The versatility of the tool will be demonstrated by modeling three mounting structures that have been experimentally verified. These mounting structures include two plane stress problems and a plane strain problem.