指叉換能器三維模型之建立與特性分析

Study of the characteristics of interdigital transducers with 3D FEM model

廖韋程(Wei-Cheng Liao)

指導教授 ： 王曙民

義守大學/智慧科技學院/電機工程學系/碩士(2023年)

摘要

指叉換能器(interdigital transducer, IDT)是表面聲波元件(surface acoustic wave devices, SAW devices)是主要用來激發表面聲波結構，而影響IDT特性之設計參數包含有IDT週期(𝜆𝐼𝐷𝑇)、重疊長度(𝑊)、電極金屬厚度(h)、連接IDT使有打線空間的匯流排(bus-bars)(XX)、IDT與bus-bars之間距(IDT-spacing)，以及可以使用假電極(dummy)長度(DX)等，雖然表面聲波元件之頻率響應，如輸出入阻抗、插入損耗等二次效應(second-order effect)已知可應用表面聲波正交場模型(crossed-filed model)[31-33]來等效表面聲波元件之指叉換能器等。本論文使用基於有限元素法(Finite Element Method, FEM)的多物理場模擬軟體COMSOL Multiphysics為工具，以建立指叉換能器之三維模型為分析案例，期能透過模擬之電氣特性與模態響應，更瞭解表面聲波元件之工作原理。

關鍵字

指叉換能器 ； 三維模型 ； 有限元素法

並列摘要

The interdigital transducer (IDT) is a surface acoustic wave (SAW) device primarily used to excite surface acoustic wave structures. The design parameters that affect the characteristics of the IDT include the IDT period, overlap length, electrode metal thickness, bus-bar spacing for connecting the IDT, spacing between the IDT and bus-bars, and the length of dummy electrodes that can be used (DX). Although the frequency response of surface acoustic wave devices, such as output/input impedance and insertion loss, is known to be influenced by second-order effects, such as the crossed-field model, the IDT can be effectively characterized using the crossed-field model. This paper utilizes the finite element method (FEM)-based multiphysics simulation software, COMSOL Multiphysics, to establish a three-dimensional model of the interdigital transducer as an analysis case. The aim is to gain a better understanding of the working principles of surface acoustic wave devices through simulation of their electrical characteristics and modal response.

並列關鍵字

interdigital transducer ； 3D FEM model ； Finite Element Method

參考文獻

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