在點對點無線通訊的系統中，其天線通常要求高增益和高指向性的天線效能。傳統上雖可用碟形天線達到高增益和高指向性的天線需求，但是有平面結構和低姿態特性的微帶陣列天線已在多種應用上取代了體積過大的碟形天線。然而較大尺寸的微帶陣列天線，其增益效能往往受限於饋入網路上的能量耗損。一般傳統的饋入網路由許多一分二的功率分配器串接所構成，此饋入型式導致較長的分支線段和許多轉折處，造成額外耗損的累積增加。因此，本論文首先設計了一具有新型饋入方法的偶極陣列天線，其中偶極天線元件以串聯的方式互相連結，並利用雙線傳輸線來組建偶極天線的饋入網路。雖然傳送至偶極天線元件的功率並不相等，但此偶極陣列天線的饋入排列成一幾何對稱的型式，其輻射場型仍可產生於垂射方向。由量測結果顯示，相較於一般陣列的分支饋入網路，本論文所提出偶極陣列天線，由於使用簡化後的饋入網路架構，在增加陣列天線元件數量的同時，亦可維持高增益的天線效能。
另外，本論文提出一可重置極化特性的微帶陣列天線，此天線由兩組微帶線形式的饋入網路構成。兩組微帶線饋入網路分別位於一共同接地面的上下層，可有效地避免兩組饋入網路落在同一平面上時，佈局的交錯和不便性，此饋入方法可減少能量於傳輸線上的耗損。陣列天線中的微帶天線皆由位於接地面上的兩正交槽孔所激發。一結合射頻開關的支幹耦合器連結至平板陣列天線的兩輸入端，藉由射頻開關設定，其饋入相位差可為0°、90°和180°，根據其輸入的相位差，此天線極化可為RHCP、LHCP、垂直線性極化和水平線性極化。因此本論文所提出的天線結構可達到極化多樣性，且藉由模擬和量測結果提供此天線效能的驗證。
最後，本論文針對無線區域網路頻段提出一具有雙頻特性的陣列天線設計，分別利用槽孔陣列天線和偶極陣列天線來設計2.4 GHz和5 GHz兩頻段操作的陣列天線，並在同一空間中將兩天線結合，增加空間的利用度，且達到雙頻與高增益的輻射特性。

Point-to-point communications requires high gain and high directivity antennas. Besides the conventional dish antenna solution, the array antenna, which has planar structure and low profile, is an usual alternative. However, the gain performance of large scale array antenna is often limited by the loss on the feeding network. A traditional feeding network comprises cascaded one-to-two power dividers, which usually results in long branches and many corners. Substantial losses are therefore accumulated. In this work, a dipole array was devised with a novel antenna feed scheme. The dipole elements are connected in a serial fashion with a straight pair wire transmission line to form a dipole branch. Although the power delivered to each dipole elements are not equal, the dipole array still yields a boresite pattern since dipole branches are arranged in a symmetric fashion. The measurement results show that due to the simple feeding structure, the proposed array antenna retains a higher gain comparing to arrays with convention branching feeds.
A four patch array antenna with reconfigurable polarization feature is proposed in this work. The antenna comes with two sets of feeding network made of microstrip lines. Instead of awkwardly laying out two feeding networks on the same plane, they occupy the top on bottom surfaces of the ground to avoid collision. Such a feeding scheme helps reduce losses on transmission lines. Each patch antenna element is excited by two slots on the ground plane placed perpendicularly. A hybrid coupler controlled by RF switches is connected to the two feed sets. By adjusting the RF switch settings, the phase difference of two feeds can be 0, 90, or 180 degrees. According to the phase difference value, the array antenna polarization can be either RHCP, LHCP, vertical LP or horizontal LP. The proposed antenna configuration can therefore achieve polarization diversity. Performance validations are provided by simulation and measurement results.
Finally, a dual band array antenna is presented in this work to operate in 2.4 GHz and 5 GHz bands of WLAN application. A slot array for 2.4 GHz and a dipole array for 5 GHz operation are combined in the same space to deliver dual band operation while maintaining decent isolation performance. Measurement results show high gain performance is achieved for both bands.

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