一種具阻抗轉換之序列式旋轉饋入電路及其在寬頻圓極化天線陣列之應用

Abstract

本論文主要研究序列式旋轉饋入電路及其在天線陣列之應用。本論文前半段先針對現有文獻中有關序列式旋轉饋入電路之研究進行分析與整理，並深入探討其物理機制與等效電路，使吾人掌握其設計技巧與效能特性；接著以此基礎，提出一個新的公式及設計方法，並以實作量測獲得驗證。後半段則延續論文前半段的推導，探討天線元件與序列式旋轉饋入電路之間的作用關係，進一步提出一個適合序列式旋轉技巧的天線，以搭配前半段提出的新型序列式旋轉電路設計，實現在正向輻射圓極化增益3dB頻寬為49%，軸長比頻寬達46%的圓極化天線陣列。模擬與量測結果也都顯示相當一致。

This thesis presents a study of sequential rotation feeder and its applications for circularly polarized antenna array. In the first half of this thesis, we survey several approaches of sequential rotation feeder network in the literature and analyze the principle and design techniques. Using an equivalent circuit model, we develop a new method on designing a compact sequential rotation feeder with the impedance transformer embedded. In the second half of this thesis, we investigate the effects of the imperfect impedance matching between the antenna elements and the sequential rotation feeder network. It is found that an antenna element with broadband minimum reactance is more suitable for the sequential rotation feeder. Furthermore, we illustrate the proposed method with two prototypes of PCB antenna arrays. The promising results are achieved, including the 3-dB axial ratio bandwidth around 46% and the co-polarized 3-dB gain bandwidth about 49% in the broadside of the antenna array. The simulation and experimental results also show a good agreement in this study.