温度补偿型声表面波谐振器的非线性分析

Nonlinear analysis of temperature-compensated surface acoustic wave resonators

温度补偿型声表面波(TC-SAW)器件的非线性研究对高性能射频滤波器的优化设计非常重要.本文充分结合几何、材料和体波非线性影响因素,从有限振幅声波非线性电-弹理论出发,推导了高阶非线性偏微分波动方程及其弱解形式,建立准3D有限元非线性模型计算TC-SAW谐振器的非线性响应精确解.在不同结构条件下,仿真与测量结果一致.利用二阶电荷量代替二阶谐波响应,阐明了非线性体波模式产生的机理.全面考虑不同非线性效应和不同材料非线性常数对高阶谐波的贡献,计算结果表明高阶谐波主要受到非线性弹性效应的影响,且SiO;高阶材料常数对非线性贡献最大.

Research on the nonlinearity of temperature-compensated surface acoustic wave(TC-SAW) devices is paramount for the optimal design of high-performance radio frequency filters. In this study, geometric-, material-, and body-wave nonlinear factors were combined on the basis of the finite-amplitude wave nonlinear electroelastic theory. A high-order nonlinear partial differential wave equation and its weak form were derived, and a nonlinear finite element model was established to calculate accurate solutions of nonlinear responses of a TC-SAW resonator. Under different structural conditions, the simulation and measurement results agreed well. Using the second-order quantity of electric charge instead of the second-order harmonic response, the generation mechanism of a nonlinear body-wave mode was clarified. Considering the contribution of different nonlinear effects and different material constants to high-order harmonics, the calculation results showed that high-order harmonics were mainly affected by nonlinear elastic effects;the high-order material constants of SiO;’s contribution was the most significant.