根据分层介质理论精确求解压电基片和金属膜中的声波,计算了声表面波传播速度、机电耦合系数、静电容。结合陈-Haus理论,分析了短路栅阵的声表面波的传播特性,得到新的单电极栅阵栅条反射系数计算公式。计算了X-112°YLiTaO3上镀铝和ST石英上镀金两种情况下的耦合模模型参量,理论计算结果和国际上通用的Hashimoto程序计算结果吻合较好。实验测定了ST石英上镀金的反射系数,测试结果和理论结果更加符合。
Accurate solutions of acoustic waves in piezoelectric substrate and metal film with layered structure were obtained. Phase velocity, electromechanical coupling constant and static capacitance were calculated based upon the solutions. Chen and Haus' theory was used to analyze surface acoustic waves in shorten gratings with single finger every period and a reflection coefficient expression of one strip was presented. Parameters of Al on X-112°Y LiTaO3 and Au on ST-quartz were calculated. The results agreed well with those from Ken-ya Hashimoto's theory. The reflection coefficient of Au on ST-quartz was measured to verify the theoretical result.