在無線通訊及雷達系統中，多重輸入輸出(Multi-Input Multi-Output, MIMO)概念已逐漸被使用到相關應用中。其中在MIMO雷達系統中，天線傾向於寬頻的設計，因此對天線間隔離度的需求就得考慮到寬頻的特性，但要同時達到良好隔離度及寬頻操作會是MIMO天線設計上的困難點之一。在本論文中，我們針對MIMO 雷達系統的C頻段設計了由共平面波導所構成的寬頻天線單元，並達到在天線間具備良好的隔離度。
我們利用互補式的概念提出在天線共平面波導饋入的接地面上延伸出和輻射貼片互補的結構來達到寬頻特性，其中提出的天線單元在考慮雙天線情況時，會由於所設計的特殊互補結構而具有提升隔離度的效果，並在天線間的接地面上設計一個U形槽孔，來改善4~8 GHz頻率範圍的隔離度都達到18 dB以上而有寬頻操作。

In the wireless communication and radar systems, MIMO (Multi-Input Multi-Output) concept has been gradually adopted to relevant applications. In the MIMO radar systems, antennas tend to be broadband design, and therefore the requirement for isolation between two antennas with broadband characteristics should be considered. However, it is difficult to have good isolation and broadband operation simultaneously in MIMO antenna designs. In this thesis, we design a broadband coplanar waveguide antenna element and achieve good isolation between two antenna elements in the C-band for MIMO radar systems.
We use the complementary concept to extend a structure that is complementary to the radiation patch from antenna ground plane of coplanar waveguide fed to achieve broadband characteristics. For the dual antenna situation, the isolation between two antenna elements will be enhanced due to the special complementary structure design. To obtain broadband operation in MIMO antenna systems, a U-shaped slot is etched on the ground plane, and a good improvement of broadband isolation above 18 dB from 4 GHz to 8 GHz is achieved.

論文審定書 i
致謝 ii
中文摘要 iii
Abstract iv
目錄 v
圖表目錄 vi
1. 序論 1
1.1 研究動機及目標 1
1.2 研究背景 1
1.2.1 共面波導[3] 1
1.2.2 寬頻單極天線[4],[5],[6] 2
1.3 互補式天線結構[7],[8],[9] 5
1.4 論文章節介紹 8
2. 天線設計 9
2.1 前導概念 9
2.2 天線模型 9
2.3 特性分析 12
3. MIMO天線設計 14
3.1 MIMO概念分析 14
3.2 設計內容 16
3.2.1 比較不同的天線擺放位置 16
3.2.2 隔離度分析[10] 20
3.2.3 改善隔離度效果之U形槽孔[11],[12] 26
3.3 天線輻射場型 37
4. 天線實作及量測 41
4.1 單一天線的量測分析 41
4.2 MIMO天線量測 42
5. 結論 44
參考文獻 45

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