利用共平面波導和微帶線的饋入架構實現雙極化天線

Abstract

本論文提出一應用於無線通訊系統及全球定位系統的雙極化天線：利用共平面波導和微帶線的饋入架構將線性極化及圓極化整合於單一架構中。線性極化經由共平面波導下方加入一條微帶線使其激發共平面波導中的兩條槽孔而產生，應用於WLAN(Wireless Local Area Networks)及WiMAX(Worldwide Iteroperability for Microwave Access)，操作頻帶分別為2.4GHz到2.484 GHz及2.5GHz到2.69 GHz。圓極化則是經由接地金屬中突出一T字形金屬細線，朝向槽孔的中央，藉由50歐姆的共平面波導訊號線饋入而產生，應用於全球定位系統(Global Positioning System, GPS)，操作頻帶在1.575 GHz。整體天線架構簡易，無堆疊結構。詳細的天線設計分析與量測結果亦將於本論文探討。

A dual-polarized antenna for wireless communication system and global positioning system is proposed in this thesis. Linear polarization and circular polarization are integrated in a single planar structure using coplanar waveguide and microstrip line feed. Adding a microstrip line below the coplanar waveguide, linear polarization is excited by the two slots in the CPW feed. The operating frequencies are ranging from 2.4 GHz to 2.484 GHz for WLAN application and from 2.5 GHz to 2.69 GHz for WiMAX application. The circular polarization is achieved by protruding a T-shaped metallic strip from the ground plane toward the slot center and feeding the antenna using a 50 CPW. The operating frequency is at 1.575GHz for GPS application. The overall antenna structure is simple and needs no stack structure. The details of the antenna design and experimental results are both presented and discussed.