適用於高鐵環境之WiMAX波束切換陣列天線設計

許多交通工具都逐漸與無線通訊產品有關，特別是在高鐵上的無線通訊產品，會因為高鐵的高速移動、電信業者的基地台資源以及基地台天線等等的問題，使得通訊品質並不良好，特別是在隧道之中經常有斷訊的問題。其主要原因是在隧道內不管是車廂內還是隧道外基地台的電磁波都無法傳達，因此要改善通訊問題則需架設小基地站於隧道之中；因此假如佈建的小基地站是使用全向性天線與高鐵車廂上方加裝全向性天線的情況下，雖然可以改善通訊問題但是因為全向性天線，在訊號的接收與傳遞上都有嚴重的互相干擾問題，使得通訊品質提升有限。因此本文製作及量測一個應用於2.55GHz的波束切換式陣列天線，來解決隧道內的通訊問題。因為波束切換式陣列天線可以切換不同角度的波束來傳送及接收訊號，一方面可以降低周遭的干擾雜訊信號，以增加信號干擾雜訊比，另一方面使得多重輸入多重輸出效果更加完善，進而提升系統效能與通訊品質。本文設計一組微帶陣列天線利用微帶天線的單一面指向性與陣列天線的高增益特性，進而使得傳統上使用全向性天線的波束切換式陣列天線系統，將具有水平角抑制在-10dB以下以及縮小主波束寬度至37.5°左右的效果，以符合高鐵隧道環境中的種種問題進而提升通訊品質，最後本論文在天線擺放方式上除了有傳統的一直線擺放方式之外，還有梯形與正方形兩種擺放方式，以提供多元且不同選擇的波束切換角度。

關鍵字

陣列天線； WiMAX ；巴特勒矩陣

並列摘要

In nowadays, many transportation provide wireless communications access, such as in the high-speed rail. The performance of communication links are affected by the high speed moving, resources of base station, and the base station antennas deployment etc. The signals will be blocked in the tunnel. Thus, small base stations are deployed in the tunnel for improving the quality of communication. At many cases, a small base station with omni-directional antenna is installed on the top of high-speed rail cars for improving the quality of communication. However, using omni-directional antennas at both receiving and transmitting sides will cause serious interference problems. This paper produces and measures a switched beam antenna array for WiMAX system at 2.55GHz to resolve the inside tunnel communication problems. The advantages of using switched beam antenna array system can reduce the interference noise from different angles, increase the signal to interference ratio, and improve the multi-input multi-output system performance and have better quality of communication performance. In this thesis, a microstip antenna array with single-side directional radiation and high gain characteristics is designed. The proposed switched beam antenna array system can suppress horizontal sub-lob up to -10dB and the main beam width can be narrowed to 37.5° which can meet the requirement of the tunnel environment and thus improve the quality of communication problems. In addition to the traditional linear deployment stratagem, there are two kinds of trapezoidal and square deployment are proposed in this thesis to provide multiple and different choices of beam selection angles.

並列關鍵字

Array Antenna ； WiMAX ； Butler Matrix

參考文獻

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國際替代計量

適用於高鐵環境之WiMAX波束切換陣列天線設計

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