Development of High-Level Design System for Raising the Performance of Surface-Acoustic-Wave Devices

声表面波（SAW）器件设计CAD系统的性能受到模拟过程精度的限制。SAW器件的精确仿真必须考虑纯电、声和混合电声效应。本计画的目的是开发一个高阶的设计系统，用于各种声表面波元件。主要研究结果如下：1.本文提出了一种基于有限元法的数值方法，用于分析实际声表面波器件中经常出现的任意形状的周期性声表面波波导，如声表面波叉指换能器（IDT）、声表面波反射器和声表面波谐振器.本文用等效网络理论和耦合模理论分析了声表面波叉指换能器的激励特性和声表面波谐振器的反射特性。等效网络的电路参数和耦合模式方程的耦合系数和换能系数可以通过将有限元法应用于对应于电短路或开路IDT的无限阵列而从理论上确定。并利用有限元法计算了一对叉指换能器的静态电容.基于有限元法，提出了一种计算YIG薄膜中静磁波传播的统一方法。

The performance of a CAD system for the design of SAW (surface acoustic wave) devices is limited by the accuracy of the simulation procedure. A precise simulation of SAW devices must take into account pure electric, acoustic, and mixed electroacoustic effects. The purpose of this project is to develop an high-level design system for various SAW devices. Results obtained are as follows:1. A numerical approach based on the finite element method has been developed for the analysis of arbitrarily shaped periodic SAW waveguides which frequently appear in the actual SAW devices, such as SAW interdigital transducer (IDT), SAW reflector, and SAW resonator.2. An equivalent network theory and a coupled mode theory are developed for the analysis of excitation characteristics of SAW-IDT and of reflection characteristics of SAW qratings. Circuit parameters of equivalent networks and coupling and transduction coefficients of coupled mode equations can be theoretically determined by applying the finite element method to an infinite array corresponding to an electrically shorted or open IDT. The finite element method is also used to calculate the static capacitance for one pair of IDTs.3. A unified numerical approach based on the finite element method is developed for the magnetostatic wave propagation in a YIG film.