Generalized Multiphysical Fields Coupled Model of SAW Resonators: From Methodology to Applications

Multiphysics modeling is crucial in surface acoustic wave (SAW) resonators. Existing coupling methods primarily focus on the displacement and electrical potential originating from the piezoelectric effect. As SAW technology advances, novel interaction mechanisms introduce new challenges in multiphysics modeling. In order to address these complexities, simulations must incorporate additional physical fields, such as semiconducting, thermal, and other fields. This study presents a comprehensive methodology for multiphysics coupling in SAW resonators, categorizing the couplings into direct and indirect types based on whether they occur through constitutive relations or through initial and boundary conditions. For direct coupling, we extend the intrinsic piezoelectric effect to piezoelectric and semiconducting coupling via constitutive laws as an illustrative example. Specifically, we simulate the electromechanical (EM)-carrier coupling in a multilayered SAW resonator, providing insights into the parasitic surface conduction (PSC) effect. In contrast, indirect coupling involves physical fields with frequencies significantly lower than that of SAW. As a representative case, we analyze the bidirectional interaction between the thermal field and SAW, where the bias field is simplified into initial and boundary conditions. A thermoelastic model using the sequential algorithm is proposed to predict the temperature coefficient of frequency (TCF) and the self-heating effect in multilayered SAW structures. Simulation results demonstrate excellent agreement with experimental data. Based on these findings, we propose optimization strategies to enhance the performance of SAW resonators.