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標題: | 二維矽基聲子晶體平板之共振腔量測 Measurements of Cavity Resonances in 2-D Si-Based Phononic-Crystal Plates |
作者: | Kuan-Luan Shan 單貫綸 |
指導教授: | 吳政忠(Tsung-Tsong Wu) |
關鍵字: | 板波,聲子晶體平板,共振腔,交指叉電極,頻溝,品質係數, Lamb waves,phononic crystal plate,Band gap,IDTs,resonant cavity, |
出版年 : | 2010 |
學位: | 碩士 |
摘要: | 聲子晶體是由兩種或多種彈性材料依週期性排列而成的人造材料。當聲波在聲子晶體結構中傳遞時,由於週期性結構造成其波傳頻散曲線不連續,使得聲波無法在該不連續的頻段內傳遞,一般稱為頻溝效應(acoustic band gap)。在頻溝範圍之內,若將無窮週期排列的聲子晶體移除一排或數排,形成的線缺陷可視為一個共振腔(resonant cavity)。
本文以布拉格理論(Bloch)為基礎,使用有限元素法(Finite Element Method)來分析二維矽基聲子晶體平板之頻溝現象,並使用超晶格技術(supercell technique)模擬其共振腔內之共振模態。同時配合穿射係數(transmission coefficient)之計算來驗證聲子晶體頻溝效應及缺陷共振腔內之共振模態,並針對共振腔兩側聲子晶體反射層層數對應於共振模態之間關係進行模擬及探討。 在實驗方面,本研究利用微機電製程製造出一層狀薄板量測結構。針對不同聲子晶體反射層層數之共振腔進行量測與探討,成功在約196 MHz處量測到一共振模態,其實驗結果與計算模擬結果相符。文中並進一步利用品質係數(Quality factor)分析實驗結果:當共振腔兩側之聲子晶體排數增加時,其共振腔內之共振模態的品質係數越高、能量越趨於穩定。 In recent years, there is a great interest in the study of periodically arranged composite elastic materials called phononic crystals. The most important phenomenon of the phononic crystal is that there is no wave propagation in a specific frequency range due to the band gap effect. Accordingly, a resonant cavity can be constructed by removing one or several lines of periodic fillers from a phononic structure. In this thesis, the Finite Element (FE) Method is adopted to predict the dispersion relation of two-dimensional air/silicon phononic crystal plates. The transmission coefficient of a resonant cavity is calculated and discussed with different layers of phononic crystals. Based on the simulated results, ZnO/Au/Si layered plates with square lattice Air/Silicon phononic crystals were fabricated by the CMOS process in order to detect and study the characteristics of the resonant mode. The experimental results show a resonant mode exists at about 196 MHz. The effect of resonant cavity with phononic crystals is in a good agreement with the numerical predictions. In addition, the results show that the Quality factor of the resonant mode can be increased up to about 1227 using six layers of the phononic crystals. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/48704 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
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