寬頻低軸比之雙埠雙圓極化天線設計

Abstract

本篇論文著重在雙埠雙圓極化天線陣列的探討，利用饋入網路實現天線陣列配合序列旋轉圓極化法降低圓極化天線陣列的軸比與增加天線的頻寬，將整個雙埠雙圓極化天線系統，分成天線與饋入網路兩部分，先行設計單元天線，作出圓極化的單元天線，在將單元天線擺成天線陣列，再配合饋入網路的設計結合序列旋轉圓極化法，進而增加極化的純度，設計可滿足低軸比寬頻之天線陣列。文中進行了單元天線的設計、天線陣列的放置以及饋入網路的設計，最終選擇達成8埠雙序列迴轉圓極化天線的饋入網路設計進行模擬與實作形成雙埠雙圓極化天線陣列驗證理論。 此8埠雙序列迴轉圓極化天線陣列饋入網路分為兩個設計，一個為4個雙圓極化的微帶線貼片單元天線組成與另一個8個單圓極化的微帶線貼片單元天線組成，利用左圓極化 、 、 、 與右圓極化的 、 ﾟ、 、 饋入方式，可對個別微帶線貼片天線上進行饋入，達成寬頻低軸比的雙圓極化天線設計。最終我們實作了一支操作在2.01GHz-2.93GHz頻帶範圍內之低軸比雙埠雙圓極化天線。

Abstract In this thesis, we focus on dual port dual circularly-polarized antenna. By using sequential rotation circular polarization method to reduce the axial ratio of the circular polarization and increase the bandwidth of the antenna array. The dual port dual circularly-polarized antenna system can be made into two parts – the antenna array and the feeding network. First, we design the circularly-polarized antenna as unit antenna. Then, we make the circularly-polarized antenna array by the unit antenna and combine with the feeding network which is design with sequential rotation circular polarization method. Furthermore, we would introduce the design of the unit antenna, the placement of the antenna array and the design of the feed-in network which are finally selected. Finally, we simulate and implement the 8-port dual-sequential rotation circular polarization antenna feed-in network form a two port dual circular polarized antenna array. The antenna array has two design. One is using four dual circular polarization unit antenna. The other is using eight single circular polarization unit antenna. Moreover, the feed-in network would excite phase arrangement – [0 ,90 ,180 ,270 ] for LHCP and RHCP. To conclude, we successfully make the dual port dual circularly-polarized antenna which is low axial ratio in 2.01GHz-2.93GHz.