近年來，多重輸出輸入通訊天線的研究在行動裝置及雷達科技的應用引起相當大的關注。在雷達科技的應用上，天線需要能寬頻操作以及好的天線增益。於本論文中，我們設計了應用於C-頻段(4-8GHz)雷達頻段的寬頻多重輸出輸入天線，並且引入reaction theorem提昇寬頻隔離度，接著藉由加入特殊設計的覆板，使天線的增益上升。

首先，我們設計了使用共平面波導饋入的多重輸出輸入天線，此種饋入方法的優點在於寬頻阻抗匹配容易。而我們設計的天線結構的概念近似於接地面於兩天線間突起的結構，天線間的隔離度已有不錯的表現，而為了補足雷達頻段內隔離度不足的部份頻段，我們引入了reaction theorem的原理應用，藉由創造等效磁流進行感應電壓的抑制，藉此達成寬頻多重輸出輸入天線的設計。

接著，為了提升雷達頻段內天線的增益，我們引入了三層設計的覆板。藉由分析天線上xz, yz平面上的電場，在覆板上相對應的位置加入金屬線結構，藉此加強天線增益。比起一般的覆板設計，三層設計的覆板擺放的位置距離天線僅四分之一波長，加強的增益約為1~3dB。

Recently, the concept of MIMO communications has created considerable attention both in mobile communications and advanced radar technology. In MIMO radar technology, the antenna should be capable of operating in wideband and high gain. In this thesis, we design a C-Band MIMO antenna for MIMO radar applications by introducing reaction theorem to enhance wideband isolation, and adding superstrates with special designs to improve gain enhancement.

First, we propose coplanar waveguide (CPW) to feed multi-input multi-output (MIMO) antenna. We choose CPW feeding because it provides the advantage of wideband impedance matching. Our antenna structure is similar to protruding structure, which provides isolation enhancement. In order to further improve the isolation over the desired frequency band, the reaction theorem is applied. By introducing equivalent magnetic current, the induced voltage can be suppressed. So that wideband MIMO antenna design can be done.

In order to enhance the gain over C-band, three stacked superstrates are proposed. By analyzing the electric field on the xz, yz plane of the antenna, we create a metal strip on the corresponding location on the superstrate to enhance gain. Compared with common superstrate, three stacked superstrates are placed only at a distance of 0.25λ, with a gain enhancement of 1~3 dB.

論文審定書........................................................................................................................i
致謝...................................................................................................................................ii
Abstract............................................................................................................................iii
摘要..................................................................................................................................iv
目錄...................................................................................................................................v
圖次.................................................................................................................................vii
表次..................................................................................................................................ix
第一章 序論.....................................................................................................................1
1.1 研究動機及背景.......................................................................................1
1.2 研究方法...................................................................................................2
1.3 相關研究概況...........................................................................................2
1.4 論文大綱...................................................................................................3
第二章 多重輸出輸入天線設計.....................................................................................4
2.1 多重輸出輸入天線設計...........................................................................4
2.2 多重輸出輸入天線隔離度設計...............................................................8
2.3 實作與模擬探討.....................................................................................12
第三章 多層覆板設計...................................................................................................18
3.1 覆板基本介紹及其應用.........................................................................18
3.2 多層覆板原理與設計.............................................................................20
3.3 實作與模擬探討.....................................................................................30
第四章 結論...................................................................................................................35
參考文獻.........................................................................................................................36

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