應用於C頻帶通訊系統之寬頻印刷天線陣列設計

Design of wideband printed antenna array for C-band communication system

余仕偉(Shih-Wei Yu)

指導教授 ： 劉文忠

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2008年)

摘要

近年來，平面結構之陣列天線已有些相關文獻發表，其多採用低介電係數基板，使天線具有較佳之操作頻寬，然所設計出之天線，大多有面積甚大及頻寬不夠大之缺點。因此，本論文將以成本低廉之FR4玻璃纖維基板，利用微帶線饋入及多層結構槽孔耦合技術來設計一可應用於C 頻段、頻寬可達1 GHz之陣列天線。
本論文第一個部份為設計可用來排列陣列天線之天線單體，利用電磁模擬軟體設計分析該天線結構，瞭解該天線在各種結構長度下，對反射損耗(return loss)之影響；第二部份則為饋入網路設計，要將天線單體以陣列方式排列，需要搭配饋入網路來傳輸信號，饋入網路與陣列天線的阻抗匹配與否將會影響陣列天線之傳輸效率。本研究之饋入網路設計使用微帶線阻抗分析與四分之ㄧ波長轉換分析，並且利用電磁軟體模擬分析此饋入網路應用於2×2陣列天線時之反射損耗及場型圖；第三部份則將2×2陣列天線擴大排列為4×4之陣列天線，並且模擬分析此一4×4陣列天線之反射損耗圖，陣列天線增益及3D場型圖，並實際製作此陣列天線以進行實驗量測；第四部份為對此4×4陣列天線作優化以得到最佳操作頻寬，並研究天線陣列場型的適應性；優化部份為利用增減基板材料厚度及在天線之輻射貼片上鑿槽孔之方法來增加其頻寬，並進行此一優化後之天線實體製作量測，以得到其實際的場型及天線增益值；最後，則對天線陣列場型進行調變，利用改變每一4×4天線陣列各饋入訊號之振幅及相位，來達到天線陣列之輻射指向可調的效果。

關鍵字

天線陣列；C頻帶；寬頻

並列摘要

Recently, some planar array antennas have been presented in literature. In most of these research works, microwave substrates with low permittivity were used to achieve good operation bandwidth. However, such an antenna design is still with either large antenna size or small impedance bandwidth for practical application. Therefore, this research is focused on designing an broadband array antenna by using the multi-layer aperture-coupled method and the microstrip feed network. The obtained impedance bandwidth of the proposed array antenna reaches 1 GHz and which is suitable for C-band satellite communication use.
The first topic of this thesis is to design a single antenna element with broad bandwidth for future use in the array antenna. The electromagnetic solver was used to analyze for the frequency response of return loss and then decide the antenna’s optimal geometry parameters. The second topic is focused on design of a microstrip-line-fed network for use in an array antenna. The impedance matching condition between the feed network and the array elements will seriously affect the transceiving efficiency of the array. The feed network was designed based on microstrip circuit analysis and quarter-wavelength impedance transformer methodology. By using the electromagnetic simulation software, the return loss and radiation pattern of a 2×2 antenna array fed by the designed feed network has been studied. The third topic goes forward to expanding the antenna array from 2×2 to 4×4. In addition to simulate the antenna’s return loss, antenna gain, and the prototype of such an array has also been constructed and experimentally studied. As for the final work, it was put on optimization of impedance bandwidth and adaptability of radiation pattern for the proposed 4×4 array antenna. The investigation shows that the wider bandwidth can be achieved from adjusting the substrate’s thickness as well as embedding a slot to the patch, while the desired radiation direction can be obtained by properly composing the feeders’ amplitudes and phases.

並列關鍵字

antenna ； C-band ； wideband

參考文獻

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