在現今的通訊系統中，例如：WLan和藍芽系統，不僅需要抑制倍頻效應，亦需要抑制雜訊（ex: image frequency），所以本論文主要設計與分析用於通訊系統濾波器之傳輸零點，以有效滿足以上的需求。

　　文中首先描述以堆疊的方式設計需要大電容之規格的濾波器，並以此方式設計具有電容性耦合與電感性耦合的濾波器以抑制雜訊，並改變其共振器的結構使濾波器在倍頻附近產生一個傳輸零點，以抑制其倍頻效應，並做了饋入點對於傳輸零點漂移的分析，期望能夠讓此結構的濾波器的設計更系統化。

　　由實測結果發現，電容性耦合結構通帶介入損失約為-1.6dB，衰減量在2.1GHz約為37dB，在5GHz大於40dB；電感性耦合結構通帶介入損失約為-2.2dB，衰減量在2.4GHz約為40dB，在5GHz附近大於60dB。由量測結果證實這些設計均能抑制雜訊和倍頻效應以符合通訊系統的要求。

　In Bluetooth and Wireless lan system, their specifications require suppressing not only spurious response but also noise owing to local oscillator. In this study, we focus on characteristics of transmission zeros of microwave passive filters.

　In this study, because we need large capacitances to satisfy the specifications of widerbandwidth, and realize those capacitances all in parallel. And by this concept, we design and analyze filters which can suppress noise, one is capacitive coupling and another is magnetic coupling. And, in above two structures, there are transmission zeros which can suppress spurious response, and we have a systematic design flow to explain the phenomenon. At last, we analyze the characteristics of transmission zeros with different
feed point.

　By measured results of the capacitive coupling structure is as follow, insertion loss of passband is about -1.5dB and attenuation is about 37dB at 2.1GHz and is larger than 40dB at about 5GHz. And the results of magnetic structure is as follow, insertion loss of passband is about -2.2dB and attenuation is about 40dB at 3GHz and is larger than 60dB at about 5GHz. The results demonstrated that these structures successfully can suppress noise and spurious response.

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