Surface-Acoustic-Wave Devices for Mobile Communication and a CAD System for the Design of Surface Acoustic Waves

点击翻译按钮获取中文摘要

The performance of a CAD system for the design of SAW (Surface Acoustic Wave) devices is limited to the accuracy of the simulation procedure. A precise simulation of SAW devices must take into account pure electric, acoustic, and mixed electroacoustic effects.In this research a coupled mode theory is developed for the analysis of excitation characteristics of SAW-IDT (Interdigital Transducer). Coupling and transduction coefficients of coupled mode equations can be theoretically determined by applying the FEM (Finite Element Method) to an infinite array corresponding to an electrically shorted or open IDT. The FEM is also used to calculate the static capacitance for one pair of IDTs. Therefore, in this approach, all the effects of piezoelectric perturbation, mechanical perturbation, energy storage, and anisotropy of a substrate are taken into account. Numerical examples are presented for the excitation characteristics of IDTs on several piezoelectric substrates such as 128^ﾟY-X LiNbO_3, X-112ﾟY LiTaO_3, 45ﾟX-Z Li_2B_4O_7, and 34ﾟY-X quartz. The computed results agree well with experimental results.