A General Fem model for Analysis of Nonlinearity in RF Baw Devices

Abstract

This article investigates nonlinear responses in bulk acoustic wave (BAW) resonators by using an originally developed nonlinear finite element method (FEM) model. This FEM model is based on perturbation analysis, which is general and effective, and its validation is performed by calculating the second-order (H2) and third-order harmonic (H3) responses of the BAW device structures with different electrode material and layer thickness. The analysis processes are explicated, and how it is carried out using traditional FEM software was demonstrated. The H2 and H3 responses calculated by FEM nonlinear analysis fit well with the experiment results without regard to impacts such as transverse mode. The proposed nonlinear FEM model can be extended to simulations of other nonlinear signals such as second-order and third-order IMDs, which allows us to know the guidelines for design of RF BAW devices with ultimately suppressed nonlinear signals.