應用於衛星訊號接收之車用圓極化天線設計

Circularly Polarized Antenna Design for Mobile Reception of Satellite Signals in Automotive Applications

林哲旭(Che-Hsu Lin)

指導教授 ： 林丁丙

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2012年)

摘要

本論文目的為設計創新的車用天線結構，應用於接收歐洲ONDAS衛星廣播系統訊號之用，其頻段使用範圍為S頻段(2.17 GHz~2.2 GHz)，為求衛星訊號覆蓋率可達整個歐洲，因此衛星廣播系統通常會嚴格規範天線在特定仰角範圍內的平均增益值，分別在仰角90度為4 dBic，仰角75~45度為5 dBic，而仰角30度則為3 dBic，同時天線亦須符合車用測試規範於1米參考地平面上進行設計。
本文針對歐洲ONDAS衛星廣播系統的需求進行車用天線設計，主輻射體為具圓極化特性的交叉偶極天線結構，饋入端採用半硬質式同軸纜線將天線建置於參考地平面的中心點，並探討天線與地平面之間的距離對於輻射場型特性之影響。此外，為達衛星廣播系統的嚴苛規範，我們採用一步階式參考接地面架構藉由改變入射至地平面之反射波相位取得天線在各個仰角增益值的平衡點，最後天線端則運用特殊彎折以及傾斜的設計改善低仰角增益值不足的問題，經由模擬驗證及實際製作量測，我們所提之天線結構能符合ONDAS衛星廣播系統的規範，並在仰角90~30度之間具備了類均向性的輻射場型，可達到穩定的衛星訊號接收，並具實際產業應用上的價值。

關鍵字

交叉偶極天線 ； 類均向輻射場型 ； ONDAS衛星廣播系統

並列摘要

The purpose of this paper is design of innovative antenna structure for reception of digital radio signals of ONDAS satellite broadcasting system within the S-band(2.17 GHz~2.2 GHz) in automotive applications, in order to achieve the reception of satellite signal which can cover the whole of Europe, the specifications and targets desired of the antenna is always more stringent than another satellite broadcasting system at specific elevation angles, the minimum average gain of +4 dBic is required at elevation angle 90, +5 dBic is required at elevation angle between 45-75 and +3 dBic is required at elevation angle 30, and the antenna should be designed above the 1-m ground plane
basis to the vehicle specification testing.
The proposed antenna is a circularly polarized crossed dipole antenna structure fed by a semi-rigid coaxial cable and mounted on the center of 1-m ground plane, first we analysis the influences on radiation pattern by varying the height between the crossed dipole antenna and the ground plane, and then a novel stepped ground plane structure is proposed to obtain an equilibrium point of average gain between high elevation angles and low elevation angles, finally, the main radiating element with a special bending and tilt design utilized to improve the average gain of the antenna at low elevation angles, the simulated results show a good agreement with the measured results to verify the proposed antenna can meet the specifications of ONDAS satellite broadcasting system, and the antenna has a quasi-isotropic radiation pattern at elevation angle between 30-90. Hence, the stable satellite signal reception can be achieved and the proposed antenna structure is suitable for practical application.

並列關鍵字

crossed dipole ； quasi-isotropic radiation pattern ； ONDAS satellite broadcasting system

參考文獻

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