微波耦合傳輸線電路為了要有更寬的頻寬，經常藉由將數段耦合傳輸線相串接來達成，但因為每段耦合傳輸線有不同的線寬與線距，當把數段傳輸線串在一起時線與線之間就會有不連續與耦合效應的產生，本論文以探討連接線效應，以定向耦合器電路為例子進行討論。
在高頻網路分析時，我們以直接運用入射波、反射波和穿透波觀念來表示，也就是散射參數。散射參數可以用電磁模擬或是向量分析儀直接測量取得，此篇論文藉由電磁模擬擷取出S參數值，再經過數學運算使S參數值轉為ABCD矩陣。藉由萃取連接線的ABCD矩陣，便可以求得連接線的響應。並且藉由訊號流程圖的分析原理對連接線的效應進行討論，以及驗證鋸齒耦合線確實可以對連接線效應進行補償。
最後以實際製作電路再次確認鋸齒耦合線，在隔離度方面，確實可以補償連接線所造成隔離度變差的問題。

Instead of using a single section of coupled transmission lines, cascade of several coupled-line sections are usually used to achieve broader bandwidth in microwave circuit designs. However, the cascade, by using connecting lines, has discontinuities and possible coupling effects due to the different widths and lengths of the coupled transmission lines. The effect of the connecting lines are studied by the analysis of coupled-line directional couplers as examples in this thesis.
For high frequency network analysis, the scattering parameters are generally used, which are defined by the incident, reflection, and transmitted waves. They can be obtained by direct measurements using a vector network analyzer, or by electromagnetic field simulations. In this thesis, the scattering parameters are obtained by EM simulations and the responses of the connecting lines are obtained by de-embedding the ABCD matrices converted from the scattering parameters. Then the effects of the connecting lines and the saw-tooth coupled lines are discussed by the principles of signal flow graphs. Experiments have been done to validate the analysis in this research.

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