表面聲波元件模型化之研究

表面聲波元件由於其具有尺寸小、重量輕、低成本、高靈敏度且符合IC製程技術等優點，固被廣泛的被應用於醫療、軍事感測、航太工程等方面，其中伴隨近年來行動通訊市場的蓬勃發展，表面聲波元件因其頻率響應範圍涵蓋1MHz~10GHz以上，已被大量製作並視為高品質因素的濾波元件(SAW filter)，同時因為影響表面聲波元件表現特性的因素諸多，因此如何針對表面聲波元件加以設計，理論上的分析以及數值模擬就更顯得重要。理論分析上CROSS與SCHMIDT於1977年提出了一套耦合模型理論(Coupling of mode, COM)，以傳輸矩陣方式求解雙埠表面聲波濾器頻率響應，但耦合理論中忽略了指叉因介質不連續所產生的反射效應，不利於單電極指叉表面聲波元件於高頻下之特性模擬，因此本論文利用梅森等效電路推導一考慮指叉電極間自耦、互耦效應的傳輸矩陣，並嘗試分析結構上各項設計參數改變，如：指叉間距、指叉重疊長度、延遲距離、壓電基板變換與指叉對數多寡，希冀提供表面聲波元件使用者於結構設計上的概念。

關鍵字

表面聲波元件；耦合模型理論

並列摘要

Because of the advantages of small size, light weight, low cost, high sensitivity and compatible to IC process, surface acoustic wave (SAW) devices are widely applied to medical and martial sensing and aviation engineering. Following with the fast growth of mobile communication, SAW devices can work in wide frequency range (1MHz~10GHz) so that it has been designed as a high quality filter. Meanwhile there are many design concepts which can determine devices property, so it appears more important to do numerical analysis and theoretical simulation before designing. In 1977, Cross and Schmidt proposed a coupling of mode theory for modeling the frequency response of SAW filters by using transmission matrix. Because of ignoring acoustic wave rejection from inter digital transducer (IDT) finger discontinuities, the coupling of mode theory can not be used to simulate the performance of single electrode SAW devices in high frequency. So we try to use an equivalent transmission matrix based on Mason equivalent model which considers manual coupling and self coupling effects to modeling SAW devices. By analyzing several parameters such as the distance between fingers, the overlap length of fingers, the length of delay line, different substrates and numbers of fingers, we expect to supply some design concepts for SAW devices designers.

並列關鍵字

SAW ； Coupling of mode

參考文獻

[11] 簡維政,“氮化鎵上氮化鋁薄膜式表面聲波元件特性研究”,中原大學電子工程系碩士論文

[1] Julian W. Gardner, Vijay K. Varadan, Osama O. Awardelkarim, “Microsensors MEMS and Smart Devices”, John Wiley & Sons, 2001, Page(s): 343-344、347-348.

[2] Supriyo Datta, “Surface Acoustic Wave Devices”, Prentice-Hall, Englewood Cliffs.

[3] D. P. Chen and H. A. Haus, “Analysis of metal strip SAW gratings and transducers,” IEEE Trans. Sonics Ultrason., Vol.SU-32. 3, pp395-408,

[5] C. K. Campbell, “Chapter 2: Basic of piezoelectricity and acoustic waves”, Surface acoustic wave devices for mobile and wireless communication, 1998.

國際替代計量

表面聲波元件模型化之研究

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