本篇論文針對現今數篇缺乏較完整合成理論之微型化平衡不平衡轉換器文獻，提出可藉由等效電路的轉換於S平面上形成帶通原型電路，再運用Wenzel帶通原型電路Exact合成方式下，得到微型化電路的完整合成理論，進而從原型電路架構觀點出發，依設計響應需求，選擇有助於電路實現性與微型化效果的原型架構，最後也嘗試運用實驗室學長們所研究的三線平衡不平衡轉換器架構設計，理論上也能達到縮減電路面積功用。

另外本篇論文也引用了180度Hybrid結構，提出具第四埠之平衡不平衡轉換器，主要目的是改善當有共模訊號於平衡輸出埠端輸入時，能有第四埠負載可以將其吸收，降低對整體電路影響，隨後又考慮到實際電路面積問題，故提出以三線平衡不平衡轉換器為主體架構，並將合成上所產生的冗餘性元件採用多條耦合線方式實現，進而形成雙三線四埠平衡不平衡轉換器電路，最後以電磁模擬與實作來驗證其合成理論。

In recent years, many miniaturized baluns structure have been suggested but complete synthesis procedures and design equations are not developed. In this thesis, the proposed baluns are synthesized based on S-plane band-pass prototypes using the Richards’ transformation. Completed exact synthesis starts at properly selection of band-pass prototypes. Circuit elements are extracted by Wenzel’s method. For the circuit implementation, the synthesized prototypes are then transformed or modified to realize circuits more effectively. To validate the proposed method, three-line baluns are synthesized, which demonstrate their size reduction theoretically.

The other topic of this thesis is exact synthesis of four-port baluns, which is derived from hybrids. The fourth port added between the balun outputs is proposed to terminate the common-mode signal that may comes from the balanced port. Four-port baluns based on the three-line balun structure are proposed for compactness consideration. Redundant elements introduced in synthesis procedures are another three-coupled-line structure. To validate the synthesis method, design examples are verified by electromagnetic simulations and experiments.

參考文獻
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