- 學位論文
表面聲波濾波器理論模擬分析與比較
comparisons of Theoretical Analysis and Numerical Simulation of SAW filter
摘要
表面聲波濾波器在通訊系統中，是一個重要的關鍵零組件。影響表面聲波濾波器表現之因素很多，所以要掌握表面聲波濾波器(SAW Filter)的品質，理論分析與數值模擬極為重要。 本文首先先對影響表面聲波濾波器性能至為關鍵的壓電基板作波傳分析，解出表面波波速及位移向量的各分量，之後利用Abbott提出的耦合模型(Coupling -of-Modes ,COM)作為分析表面聲波濾波器之理論依據，並將求得的波速與位移分量代入耦合模型參數中用以分析表面聲波濾波器中的交指叉換能器，在進而推導出二埠表面聲波濾波器之導納矩陣及傳輸矩陣，並模擬中心頻率為300MHz，不同材料的二埠表面聲波濾波器頻率響應，並比較及討論各項設計參數，如：壓電材料、交指叉電極對數、交叉長度、金屬柵欄數目對中心頻率響應之影響。接著，在將波傳分析、耦合模型、二埠表面聲波濾波器等理論作結合，應用於分析可具有大頻寬的斜交指叉式表面聲波濾波器，並模擬中心頻率為300MHz、不同的壓電材料的寬頻表面聲波濾波器之頻率響應及探討各項參數，如：壓電材料、斜交指叉電極、頻寬等對頻率響應之影響。
並列摘要
The SAW Filter is an important key element of telecommunication systems. There are many factor of the influence SAW filter, grasp the quality of SAW filter, theoretical analysis and numerical simulation are more importance. Firstly, this thesis analyze wave propagation of piezoelectric substrate because it influence surface acoustic wave filter performance most, and we can solve velocity of surface acoustic wave and displacement vectors . Then, using the coupling-of- mode(COM) model to analyze surface acoustic wave filter, we will get the answer of phase velocity and displacement vectors, and we substrate the answer to COM model for analyzing Interdigital Transducer. Then infers transfer matrix of two-port SAW filter, and simulation the frequency response of 300MHz center frequency of two-port SAW filter in the different substrate. There are some key parameters, such as the number of pairs of IDT, the cross length of the IDT, the number of grating etc., are discussed. Next, we combine the theories of wave propagation analysis, coupling-of- mode and two-port SAW filter for analyzing Slanted finger interdigital transducter (SFIT) SAW filter which have wider bandwidth, Moreover, we also simulate the frequency response of Wideband SAW filter,300MHz center frequency in the different substrate.