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標題: | 結合聲子晶體反射體之板波振盪器研製 Development of Lamb Wave Rsonator with Phononic Crystal Reflective Gratings |
作者: | Chao-Yi Huang 黃兆誼 |
指導教授: | 吳政忠(Tsung-Tsong Wu) |
關鍵字: | 板波振盪器,聲子晶體平板,金屬反射極,頻溝效應, Lamb wave resonator,Phononic crystal plate,Ban-gap,IDT,Metal grating, |
出版年 : | 2009 |
學位: | 碩士 |
摘要: | 一般的表面波與板波的振盪器,使用壓電材料和交指叉電極(interdigital transducer)來激發彈性波,並且加上金屬柵欄(metal grating)反射器來形成一個共振腔,但金屬柵欄通常反射效果有限並且需占據相當大的面積。本文引入聲子晶體的特性來改進振盪器;在聲子晶體中,由於波傳之頻散曲線不連續,造成該不連續的頻段內聲波或彈性波無法傳遞,此現象稱為頻溝(acoustic band gap)。藉由頻溝的特性可以使用聲子晶體來設計更有效率的反射器。
本文以有限元素法(Finite Element method)來分析二維矽基聲子晶體平板之頻溝現象,並且藉由計算與模擬來探討波源與聲子晶體間距離不同所帶來的影響。並以微積電實驗來完成板波振盪器與聲子晶體結構;但由於矽基材並非壓電材料,本文以氧化鋅(ZnO)薄膜來做為壓電材料,藉由交指叉電極於氧化鋅表面以壓電效應激發板波。 由實驗的結果,針對波源與聲子晶體在不同相對距離的設計下進行量測與探討,實驗結果與計算的結果相符,驗證聲子晶體和板波振盪器在合適的設計下可以有效提升振盪的效果。 In general, surface acoustic wave and Lamb wave resonator using piezoelectric material with IDTs to generate elastic waves. The resonant cavity is formed by adoption of metal gratings to be reflector. As usual, the efficiency of metal gratings is limited, and the grating structures occupy lots of space. In this thesis, the phononic crystal is imported to improve the resonator performance. The most characteristic of phononic crystals is the band-gap phenomenon, obstructing acoustic waves in a specific frequency range. The purpose is to design a resonator with higher resonance efficiency by phononic crystal reflective gratings. In this study, the finite element method (FE method) is applied to predict the dispersion relation of two-dimensional air/silicon phononic crystal plate. The effect of reflective distance between wave source and phononic crystal is calculated and discussed. Moreover, air/silicon as phononic crystal plate and ZnO/Si as Lamb wave generator are fabricated. The experimental results are measured and discussed. The effect of phononic crystal gratings is verified. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43944 |
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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