臺灣博碩士論文加值系統

本論文將研究並設計具有極化切換能力的槽孔耦合微帶天線。為了產生不同的極化，天線藉由耦合微帶線經由接地面上的環形槽孔以串聯方式激發二正交模態，並選擇適當殘枝長度以激發具有良好線性或圓極化輻射特性，除此之外，線極化也可以透過接地面上的開路環形槽孔激發，所有對於圓極化和線極化特性影響的重要參數皆詳細於本文探討。為了能使用電子裝置控制極化的變換，使用開關二極體來重置殘枝長度和環形槽孔，並成功完成了具有圓極化/線極化切換和垂直/水平極化切換的微帶天線。接著，利用具有線性極化切換的天線結構，並在圓形金屬片上蝕刻不等長的交叉槽孔，以完成左旋圓/右旋圓極化切換的設計，除此之外，也可以在圓形輻射金屬片45度角的方向放置一寄生金屬片，並加入開關二極體控制導通狀態，使天線可提供垂直/水平/左旋/右旋四種極化的切換能力。從實驗結果得知，本論文所提出之可切換極化的微帶天線操作在線性極化時，有低的交叉極化，當操作在圓極化時有很好的軸比特性。

This thesis presents the designs of an aperture-coupled microstrip antenna with switchable polarization. Two orthogonal modes of the microstrip antenna can be excited by a series microstrip-line-feed configuration through the coupling of a ring slot in the ground plane. For the ring-slot-coupled microstrip antenna, the antenna can radiate linear (LP) or circular polarization (CP) with good performances by selecting a proper length of the open stub in the feed line. In addition, the LP radiation also can be excited through the coupling of an open-ring slot instead of the ring slot. The effects of the key parameters of the proposed design on the CP and LP performances are first investigated in details. Then, by using pin diodes to reconfigure the coupling slot and the stub length, the polarizations of the microstrip antenna can be electrically switched. Different polarization switching designs have been achieved, including linear / circular polarization, dual linear polarizations, and dual circular polarizations. Finally, the aperture-coupled microstrip antenna with quad polarization switching is also designed and implemented. From the obtained results, each polarization is operated at the same frequency band and has a broadside radiation pattern with low cross polarization.

中文摘要…………………………………………………………………… i
英文摘要………………………………………………………………………… ii
致謝……………………………………………………………………………… iii
目錄……………………………………………………………………………… iv
圖目錄…………………………………………………………………………… vi
表目錄……………………………………………………………………… ix

第一章 序論…………………………………………………………………… 1
1.1概述…………………………………………………………… 1
1.2 文獻探討…………………………………………………………… 3
1.3 內容提要…………………………………………………………… 5
第二章 環形槽孔耦合之微帶天線設計………………………………… 7
2.1概述……………………………………………………………… 7
2.2圓極化天線之設計………………………………………………9
2.2.1模擬分析與實驗結果………………………………………11
2.3 線極化天線之設計(A)……………………………………………14
2.3.1模擬分析與實驗結果………………………………………15
2.4 線極化天線之設計(B) …………………………………………21
2.4.1模擬分析與實驗結果………………………………………23
2.5 結論與心得…………………………………………………28
第三章 雙極化切換之槽孔耦合微帶天線設計………………………………29
3.1概述………………………………………………………………29
3.2 具有線/圓極化切換之設計……………………………………… 31
3.2.1 實驗結果………………………………………………… 33
3.3 具有垂直/水平極化切換之設計………………………………… 41
3.3.1 模擬與實驗結果………………………………………… 44
3.4 具有左旋/右旋圓極化切換之設計………………………………49
3.4.1 模擬與實驗結果…………………………………………52
3.5 結論與心得…………………………………………………… 57
第四章 具有四極化切換之槽孔耦合微帶天線設計………………………58
4.1 概述……………………………………………………………… 58
4.2天線結構與分析………………………………………………59
4.3 模擬與實驗結果……………………………………………63
4.4結論與心得…………………………………………………70
第五章 結論……………………………………………………………71
參考文獻………………………………………………………………… 73
附錄………………………………………………………………………… 76




圖目錄

圖2.2.1 使用環形槽孔耦合饋入微帶天線的幾何結構圖。………………… 10
圖2.2.2 環形槽孔耦合微帶天線之阻抗反射損失圖與3 dB軸比頻寬圖。…12
圖2.2.3 在2440 MHz所量測之遠場輻射場型圖。……………………………13
圖2.3.1 在2440 MHz時, ls長度對圓極化特性的影響。…………………17
圖2.3.2 當ls = 33 mm時，槽孔耦合微帶天線的阻抗反射損失
與極化比特性圖。………………………………………………18
圖2.3.3 微帶饋入線上之電流分佈。…………………………………………19
圖2.3.4 量測於2440 MHz線極化天線之遠場輻射場型圖。………………20
圖2.4 弧形槽孔耦合饋入微帶天線的幾何結構圖。………………………22
圖2.4.1 不同α角度的樣品天線之阻抗反射損失與極化軸比特性圖。………25
圖2.4.2 樣品天線B在2440 MHz時，ls長度對軸比與線極化方向的影響。…26
圖2.4.3 樣品天線B在2440 MHz所量測之遠場輻射場型圖。………………27
圖3.2.1 線/圓極化切換之微帶天線幾何結構圖。……………………………32
圖3.2.2 具有線/圓極化切換之微帶天線成品圖。……………………………35
圖3.2.3 二極體操作在不同狀態下所量測到的阻抗反射損失
及極化特性圖； ls = 43 mm。………………………………36
圖3.2.4 二極體操作在不同狀態下所量測到的阻抗反射損失
及極化特性圖； ls = 47 mm。……………………………………37
圖3.2.5 天線操作在線極化時，於2440 MHz所量測的遠場輻射場型圖。…38
圖3.2.6 天線操作在圓極化時，於2440 MHz所量測的遠場輻射場型圖。…39
圖3.2.7 天線操作在圓極化時，在不同平面所量測之軸比對於θ角的變化。…………………40
圖3.3.1 具有垂直/水平極化切換之天線幾何結構圖。………………………42
圖3.3.2 具有垂直/水平極化切換之天線成品圖。……………………………43
圖3.3.3 天線操作在y方向極化時的阻抗反射損失和極化特性。……………45
圖3.3.4 天線操作在x方向極化的時阻抗反射損失和極化特性。……………46
圖3.3.5 天線操作在y方向線極化時，於2460 MHz所量測的
遠場輻射場型圖。…………………………………………………47
圖3.3.6 天線操作在x方向線極化時，於2460 MHz所量測的
遠場輻射場型圖。…………………………………………………48
圖3.4.1 具有左/右旋圓極化切換之天線幾何結構圖。………………………50
圖3.4.2 具有左/右旋圓極化切換之天線成品圖。……………………………51
圖3.4.3 天線操作在左旋圓極化的阻抗反射損失和圓極化軸比結果。……53
圖3.4.4 天線操作在右旋圓極化的阻抗反射損失和圓極化軸比結果。……54
圖3.4.5 天線操作在左旋圓極化時，於2440 MHz所量測的
遠場輻射場型圖。……………………………………………………55
圖3.4.6 天線操作在右旋圓極化時，於2440 MHz所量測的
遠場輻射場型圖。……………………………………………………56
圖4.2.1 具有垂直/水平/左旋/右旋極化切換之微帶天線幾何結構圖。……60
圖4.2.2 具有垂直/水平/左旋/右旋極化切換之微帶天線成品圖。…………61
圖4.3.1 天線操作在y方向和x方向極化時的阻抗反射損失和極化結果。…64
圖4.3.2 天線操作在左旋/右旋圓極化時的阻抗反射損失
和圓極化軸結果。………………………………………………65
圖4.3.3 天線操作在y方向極化時，於2460 MHz所量測的
遠場輻射場型圖。…………………………………………………66
圖4.3.4 天線操作在x方向極化時，於2460 MHz所量測的
遠場輻射場型圖。……………………………………………………67
圖4.3.5 天線操作在左旋圓極化時，於2460 MHz所量測的
遠場輻射場型圖。……………………………………………………68
圖4.3.6 天線操作在右旋圓極化時，於2460 MHz所量測的
遠場輻射場型圖。……………………………………………………69



表目錄

表2.4.1 不同開口角度實驗結果和相關天線參數。…….………………….…24
表4.3.1 天線的極化特性與二極體狀態關係。…………………….………….63

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