This paper aimed at extracting optimal structural parameters for Love wave device with structure of multi-waveguides to improve its temperature stability.The theoretical model dealing with the Love wave propagation in multi-waveguides was established first,the dispersion characteristic is depicted by the acoustic propagation theory of stratified media and boundary conditions.Combing with the dispersion characteristics and Tomar's method,the optimal structural parameters for the Love wave device with zero temperature coefficient were extracted,and confirmed by the following experimental results.Excellent temperature coefficient of the Love wave device with SU-8/SiO_2 on ST-90°X quartz substrate was evaluated experimentally as only 2.16 ppm/℃,which agrees well with the calculated results.The optimized Love wave device is very promising in gas sensing application.
WANG WenHOU JiaoliSHAO XiutingLIU MinghuaHE Shitang
该文提出了声表面波器件有限元/边界元(Finite Element Method/Boundary Element Method,FEM/BEM)模拟的快速计算方法.FEM/BEM方法作为一种全波分析方法,考虑了所有声波模式,能实现对声表面波器件的精确模拟,但FEM/BEM方法一般计算量大而难以实用,国内外已有工作围绕提高FEM/BEM法的计算速度展开.本文将在Ventura工作的基础上,优化占主要计算量的体波贡献.首先对固定的半无限长压电基片的格林函数用分段多项式函数近似,以避免复杂格林函数的反复计算,然后推导出近似后的积分之间的递推关系式,编写递推算法,并通过实例验证了递推算法能达到精度要求且提高了计算速度.最后采用优化后的FEM/BEM程序对一种纵向耦合(Double Mode Saw,DMS)滤波器进行模拟,模拟结果与实验结果吻合.
