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標題: | 結合聲子晶體反射體之單埠板波共振器研製 Design and Fabrication of a One-Port Phononic Plate Wave Resonator |
作者: | Chen-Yu Kuo 郭鎮宇 |
指導教授: | 吳政忠(Tsung-Tsong Wu) |
關鍵字: | 板波共振器,聲子晶體,頻溝,有限元素法,共振模態,品質因數, Plate wave resonator,Phononic crystal,Band gap,Finite element method,Resonant mode,Q factor, |
出版年 : | 2010 |
學位: | 碩士 |
摘要: | 聲子晶體是由數種彈性材料在空間中週期性排列而成,當聲波在此結構中傳遞時,由於波傳模態在某頻率範圍出現不連續的現象,使該頻段內聲波無法傳遞,此現象稱之為聲波頻溝(acoustic band gap)。本研究即利用此頻溝現象,配合數值分析及微機電製程,探討以聲子晶體為反射體之共振器的共振現象。
本文以布拉格(Bloch)理論為基礎,並結合有限元素法(finite element method, FEM)建立週期性邊界條件,分析聲子晶體之頻散關係。此外,藉由計算延遲距離(delay distance)探討等效反射面在共振腔內之位置,進而最佳化共振器之共振效果。本文也同時探討共振腔內相鄰反對稱共振模態之頻率間隙,並利用超晶格技術(supercell technique)分析其頻率間隙與共振腔長度之關係。 在實驗方面,本研究亦成功研製出具正方晶格聲子晶體反射體之矽─氧化鋅複合薄膜單埠板波共振器,其實驗結果與數值模擬相當吻合;如數值分析所預期,對於兩相異共振腔長度的共振器,亦量測到不同數目之頻率響應,驗證了共振腔長度與共振模態之頻率間隙的關係。此外,量測結果顯示,此共振器在共振頻率159.08 MHz處,具有相當高的品質因數(quality factor)。 This thesis reports numerical analysis and experimental results of a one-port plate wave resonator using two-dimensional phononic crystal (PC) gratings. Based on the band gap effect of the PC, i.e. acoustic waves in a specific frequency are blocked by the PC, PC was utilized as the reflectors of a resonator. The dispersion relations of phononic crystals were calculated by using the finite element method (FEM). To optimize the resonance inside the cavity, the effective reflective plane was obtained through a series of numerical simulations. Attention has been also focused on frequency differences between the lowest anti-symmetric (A0) modes within a resonant cavity. The relation between the cavity length and the frequency difference was analyzed by supercell technique. On the experimental side, one-port ZnO/Si plate wave resonators with square-lattice PC reflective gratings were fabricated. The measured resonant frequencies of the cavity are in a good agreement with the numerical predictions. In addition, the measurement result showed that a high Q factor of 3885 can be achieved at 159.08 MHz resonant frequency. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/48714 |
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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