運用S平面原型設計及合成寬頻被動元件

Abstract

本論文主題為使用S平面的合成技術，合成寬頻微波被動元件。傳統的S平面合成適用於寬頻傳輸線濾波器的合成。而本文將此S平面的合成技術，進一步的運用在其他寬頻微波元件上的設計。首先對鼠競環進行分析，將其等效成兩個二埠網路，並個別使用S平面高通原型合成，為了實作在平面電路上，我們使用了平衡式傳輸線，以及用Lange耦合器式結構和增強耦合式結構實現強偶合量的耦合微帶線；接著是分析並設計寬頻的平衡非平衡轉換器，我們同樣將其等效成二埠網路，並使用了S平面帶通原型合成，為了實作在平面電路上，我們使用了多種傳輸線結構，像是微帶線、槽狀線、共平面帶狀線等。集總式元件被用來近似部分的傳輸線，以達到電路的簡化及增強了止帶的抑止效果。除了使用集總式元件，我們也使用了電路的轉換，使其可更簡單的實作在平面電路上。本論文的所有電路都使用一般的單層板的製程，可以降低實作電路的成本。

The topic of this dissertation is using the S-plane synthesis technique to design the broadband microwave passive circuits. The conventional S-plane synthesis technique is suitable for designing the broadband microwave TEM filter. In this dissertation, we further use the S-plane synthesis method to other broadband microwave passive components. First, we analyze the rat-race ring hybrid. It is equivalent to two two-port networks and synthesized by the S-plane highpass prototype, respectively. To implement the circuit on a single layer board, we use the balanced transmission line. The Lange coupler structure and enhanced coupling structure are used to realize the strong coupling of the coupled line sections. Then, we analyze and design the broadband balun. The balun is also equivalent to a two-port network and synthesized by the S-plane bandpass prototype. To implement the circuit on a single layer board, we use different kinds of transmission line structures, such as microstrip lines, slot lines and coplanar striplines. To simplify the circuit and improve the stopband suppression, the lumped elements are used to approximate parts of the transmission lines in the balun. Besides, we also apply the circuit transformation to realize the balun on a single layer board easier. In this dissertation, all of the proposed circuits are implemented by the conventional single layer PCB process. It reduces the cost of circuit implementation.