製作微帶線雙頻帶濾波器，電路設計者必須了解到諧振器諧波發生位置及諧振器耦合架構，接下來則要克服兩個頻帶在輸入及輸出端的匹配問題。為了解決兩個頻帶匹配問題，文中利用到四分一波長阻抗轉換器和外部品質因數的關係式，有效的提出設計的方法。而本論文是利用均勻阻抗方形諧振器的效應來設計二倍頻雙頻濾波器，然後再增加輻射阻抗來改變偶模態發生位置，提高倍頻的自由度。最後再使用曲折的方式改變諧振器的結構並針對其耦合係數做分析，並且利用增加傳輸零點提高電路的止帶效果，最後再針對其零點發生位置進行定義，利用此種結構的方式可以有效降低面積，提高電路效能。
二倍頻與非整數倍頻都是採用FR-4基板來實現，而曲折方式雙頻濾波器則是採用氧化鋁基板來設計，其面積可縮小45%的面積。

To produce a dual-band pass microstrip filter, a circuit designer must understand determine the location that suppression oscillation frequencies of resonators and takes place and the coupling structure of resonators, and next have to overcomesolve the match problem of dual bands in the input and output ends. In order to solve the match problem, an effective design method using a quarter-wavelength impedance converter and a correlation formula of external quality factor is proposed in this study. The uniform impedance square resonator is used to design the double-frequency dual-band filter. The study showed that the even-mode impedance can be changed freely. Finally, a folding method was used to change the structure of the resonator. Analysis of the coupling coefficients was performed. The results showed that the behavior of the stop band of the circuit could be improved by adding extra transmission zero point. The proposed structure could effectively reduce the area of the circuit and promote the performance of the circuit.
To realize the folding dual-band filters, the FR4 boards and the Al2O3 boards were used. The experiments showed that both the integer and non-integer second harmonics could be excited successfully and the effective area was reduced by 45%.

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