毫米波導波管轉接及耦合設計

Abstract

本論文旨在設計38GHz 導波管與其他傳輸線之轉接與能量耦合，主要包含三種結構：﹙1﹚同軸電線至導波管之轉接設計；﹙2﹚上、下導波管間之轉接設計；﹙3﹚導波管至微帶線之耦合設計。在第一種結構中，我們將同軸電線之中心導體深入導波管中，適當設計此探針的長度及位置，達成轉接目的。在第二種結構中，我們在上、下導波管之共同金屬面中，設計適當大小及形狀的孔隙，使能量順利於此二導波管中傳遞。第三種結構則是在導波管寬面上挖槽，並於其上放置一端開路之微帶線，經由槽孔及開路長度之設計，將適當能量由導波管耦合至微帶線。對於這三種結構，我們都使用全波有限元素法之HFSS模擬分析，並獲得良好可控制的反射︱傳輸損耗及頻寬。為驗證設計的正確性，對每一種結構我們也都進行實驗量測，其結果與設計值非常吻合。

The good of this thesis is to design the transition and coupling between the rectangular waveguide and other transmission line at 38GHz, These structures are tackled: (1) Transition between rectangular waveguide and coaxial line; (2) Transition between two stacked rectangular waveguides; (3) Coupling from rectangular waveguide to microstrip line. In the first structure, the center conductor of the coaxial line is inserted into the as a probe. Energy transition can be accomplished by suitably designing the length and position of this probe. In the second structure, two symmetrically located apertures are designed on the common broad wall of the two stacked waveguides. The power coming from one waveguide can totally transmit to the other waveguide through these apertures. In the third structure, an open-ended microstrip line is placed on the broad wall of a rectangular waveguide. A slot with suitable length and width is designed on this broad wall so that a desired amount of energy can be coupled from the waveguide to the microstrip line. The commercial software HFSS, which utilizes the full-wave finite-element method, is used for the simulation of the above structures. Good performances have been achieved for all the transition and coupled configurations. Finally, the characteristics of the designed structures are measured, which show good agreement with the simulated ones.