臺灣博碩士論文加值系統

在本論文中，我們提出兩種不同型態天線設計。第一種為槽線應用於多頻帶平面天線；第二種為改善角錐型號角天線的輻射特性之新型方法。
首先文中提出一種多頻帶平面天線被設計用於4G（LTE）和Wi-Fi熱點的應用，我們使用非對稱導體之有限地面的共平面波導的基本架構當主要信號傳輸路徑。能量由下方饋入至上方金屬面，產生出兩種電流方向，再利用耦合至下方槽線產生出多種路徑，以至於達到寬頻且多頻帶的效果。接著利用側邊的短路面可以調整天線的阻抗和電流的方向，達到所有頻帶內輻射場型一致性。
第二，在衛星通信系統中角錐型喇叭天線為一個主要的研究，為了滿足低旁瓣，對稱的要求，會使用效果良好的波浪型號角天線或者介質天線。但其製作上相對困難，成本也較一般型的高。為了解決這樣的問題，我們提出一種新型的改善方式，在角錐型號角天線裡擺放金屬圓錐使其產生變化，使旁辦降低與場型輻射有一致性和重疊性，再加上加入了金屬圓錐，相位中心變化差異不大，以利與碟型天線配合使用。最後使用電磁模擬轉體HFSS、CST與FEKO相互驗證，探討實作與模擬兩者結果。

In this thesis, we propose two different types of antennas design. The first is the multiband planar antenna using slots and the second is a novel method of radiation characteristics improvements for conical horn antenna.
The multiband planar antenna using slots is designed to be used for hotspots applications of 4G (LTE) and Wi-Fi. We use the asymmetrical conductor-backed finite-ground coplanar waveguide as the basic architecture and also acts as the main RF signal transmission path. The slots with different lengths and widths are placed in parallel with each other on the top and bottom ground planes to make multiple resonances at different frequencies, and therefore, to meet the broadband requirement. These slots are also used to control the current directions and thus, to determine a special characteristic mode that always radiate in the broadside direction for all working bands. In addition, the use the partial side wall, which act as a short path, can adjust the antenna input impedance and current directions for lower frequency band.
Second, we consider the pyramidal horn antenna used as the primary feed of the reflector antenna of satellite communication systems. To meet the requirements of lower sidelobes, symmetrical and resemble radiation patterns for E-plane and H-plane, we propose a new method to improve the radiation characteristics of the feed horn. We arrange a metal cone in the central axis of the pyramidal horn antenna and the slope of this metal cone is nearly the same as that of the feed horn. The phase center point of the feed horn due to this inserted metal cone changes very little so that the relation distance between the reflector and this associated feed horn nearly the same.
Finally, we will demonstrate our design methods and the measurement and simulation results are also discussed.

目 錄
頁次
摘要 i
Abstract ii
誌謝 iii
目錄 iv
圖目錄 vii
表目錄 x

第一章 緒論 1
1-1 研究動機 1
1-2 文獻探討 2
1-3 論文大綱 3
第二章 槽線應用於多頻帶平面天線設計 4
2-1 概述 4
2-2 特徵模態(Characteristic Modes) 4
2-2-1控制電流造成所需的輻射場型 5
2-2-2 Slot -Microstrip Antenna 6
2-3 天線架構與設計概念 7
2-3-1結果圖 9
2-4 不同頻帶的輻射場型 12
2-4-1利用電流分析輻射場型 16
2-5 增益問題 27
2-6 各平面實作圖 28

第三章 波導管特性 30
3-1 概述 30
3-2 矩形波導管與其模態分布 31
3-3 圓形形波導管與其模態分布 35
第四章 波導天線 40
4-1 概述 40
4-2 各種形式的號角天線 41
4-2-1一般模態之號角天線 41
4-2-2波浪型之角錐型號角天線(Conical Corrugated Horns) .42
4-2-3 Choked Waveguide Horns 42
4-2-4 Aperture Matched Horns 43
4-2-5 Dielectrically Loaded Horns 43
4-3 號角天線重要參數 44
4-3-1相位中心(phase center) 44
4-3-2 Sidelobe Level(SLL) 45
4-3-3對稱性 .46
第五章 波導天線設計上所應用的方法 47
5-1 邊緣散射(Edge Diffraction) 47
5-2 波浪狀Corrugated的線性極化(TE11 Mode) 47
5-3 平面波(Plane Wave) 49
第六章 利用金屬圓椎設計號角天線 50
6-1 圓錐形的號角天線(Conical Horn Antenna) 50
6-1-1錐形的號角天線(Conical Horn Antenna) 結果 51
6-2 TE11模態線性化設計方法 53
6-2-1利用金屬圓錐改善圓錐型號角天線 58
6-2-2開口端場圖能量比較 61
6-2-3改善匹配效果 62
第七章 結論 64
參考文獻 65
作者簡歷 66

參考文獻
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