利用共平面波導的兩種基本模態所激發的雙極化槽孔天線

Abstract

本論文提出兩種應用於無線通訊系統之藉由共平面波導的兩種基本模態來激發的雙極化槽孔天線。我們所提出的天線設計擁有結構簡單並且易於製造的特性。利用共平面波導的兩種模態激發天線使其擁有兩種互相正交的極化方向，並且讓天線整體架構簡便。 我們提出了藉由共平面波導的兩種基本模態激發的槽孔偶極天線，分別利用共平面波導的偶模態去激發偶極槽孔以及奇模態去激發共平面波導的兩段槽孔來產生兩個互相正交的槽孔偶極天線，使得所提出的天線擁有兩個互相正交的極化方向並且簡單的結構。 我們也提出了藉由共平面波導的兩種基本模態激發的環狀槽孔天線，利用這兩種模態去激發環狀槽孔天線使其操作在兩種相互正交的極化方向，在兩個輸入埠中得到的天線增益在所需要的操作頻帶中是相當穩定且一致的，因此提出的天線是非常適合使用於雙極化的應用。 以上所提出的所有設計理論及天線架構的細節，模擬與實驗驗證，於本論文中都會加以仔細地討論。

Two kinds of dual-polarized antennas excited by two fundamental CPW modes for wireless communication systems are proposed in this thesis. The proposed designs have simple antenna structure and easy to fabricate. The two orthogonal polarizations of the proposed antennas are excited by the two modes of the coplanar waveguide feed, thus the overall antenna dimensions are kept constant and the antenna size is compact. Firstly, a dual-polarized slot dipole antenna excited by the two fundamental CPW modes is also proposed. Using the slot dipole excited by the even CPW-mode and the two slotlines in the CPW feeding structure excited by the odd CPW-mode, the proposed antenna can have two orthogonal polarizations with a simple structure. Secondly, a dual-polarized slot loop antenna excited by the two fundamental CPW modes is proposed. By exciting the two fundamental modes, the slot loop antenna can operate in two orthogonal polarizations. The measured gains of two input ports are very stable and consistent in the broadside direction over the entire operating frequency band, which makes the proposed antenna very applicable for dual polarization applications. The operating mechanism and details of the antenna design are discussed. Experimental and simulated results are both presented and discussed.