短路雙生階梯式多輸入多輸出天線設計

本論文研究分成兩個部份，第一部分為利用微帶天線設計技巧，設計可應用於無線區域網路之微帶單極天線；第二部份則利用第一部分所設計天線，利用空間、極化、場型分集來設計不同類型的MIMO天線。所提出之微帶單極天線設計採用短路針來連接階梯式的雙貼片輻射體以及在接地板上延伸金屬元件，整體尺寸僅32 x 25 mm2，激勵共振頻率在2.61 GHz和5.52 GHz，並具有710 MHz和1.56 GHz的雙阻抗頻寬，平均的天線增益分別是2.9 dBi和3.5 dBi，以及類單極天線型態的輻射場形，這些特性足使此天線適用於無線區域網路的應用，文中探討並比較有無短路針及接地板上有無突出元件對此天線在反射損耗頻率響應上的影響，其次，分析天線尺寸參數對高低頻帶的影響，以期可以更清楚的了解其激發原理及理論理與實測的應證。另提出之空間分集天線為利用兩相同之微帶天線設計並行排列在同一平面上，在適當的距離下，可以達到良好的隔離效果；設計之極化分集天線也是使用相同之微帶天線結構，利用單極天線的線性極化特性將兩天線彼此嵌合，使得軸方向彼此正交，以達成極化分集的結果；提出之場型分集天線則是設計了朝四個方向的天線，饋入部分以同軸饋入的方式，將訊號以交換的方式朝向需要的方向來達到全域覆蓋，這也是所謂的交換式分集。最後，結論上總結了本研究天線的結果。

關鍵字

微帶天線；多輸入多輸出天線；短路雙生階梯式

並列摘要

The research of this thesis is divided into two parts. In the first part, we presented a monopole antenna for WLAN application designed by micro-strip line. In the second part, we designed MIMO antennas by using the antenna presented in the first part and various types of diversity such as spatial diversity, polarization diversity, and pattern diversity. under the overall dimension of 32 x 25 mm2, the presented micro-strip antenna adopt the design of shorted-pin connected upper and lower patch in FR4 substrate and protruded the ground plane, excited resonance at 2.61 GHz and 5.52 GHz and dual impedance bandwidth of 710 MHz and 1.56 GHz, respectively. The antenna has average antenna gain of 2.9 dBi and 3.5 dBi, and has similar monopole radiation pattern. The above characteristics made the presented antenna be sufficient applied for WLAN. We also discuss and compare whether shorted pin and protruded ground plane will have some effects of the return loss to the frequency plot. Moreover, we analyze parameters of antenna structure in higher and lower frequency band so as to understand the excited principle, theory and the result of experiment can match to each other exactly. The spatial diversity antenna makes use of the two same micro-strip antennas and arranges them in parallel in the same plane, it can have good effect of isolation in the appropriate distance. The polarization diversity antenna also uses the same structure of micro-strip antenna, it takes advantage of the linear polarization characteristic of monopole antenna by lodge the two micro-strip antenna, and thus it makes the axis direction be orthogonal so as to reach the result of polarization diversity. The Pattern diversity antenna is designed with four antennas towards four directions, with this design, the fed-line offered signal to the directions we needs by the way of swap and coaxial-fed type to reach a result of all domain cover, this is the way we called switched-diversity. To sum up, the conclusion concludes the research result on antenna.

並列關鍵字

micro-strip antenna ； MIMO ； shorted twin step-patch

參考文獻

[1] P. Nepa, G. Manara, A.A. Serra, and G. Nenna: “Multiband PIFA for WLAN applications,” IEEE Antennas Wirel. Propag. Lett., 2005, 4, pp. 349-350.

[2] S.K. Oh, H.S. Yoon, and S.O. Park: “A PIFA-type varactor-tunable slim antenna with a PIL patch feed for multiband applications,” IEEE Antennas Wirel. Propag. Lett., 2007, 6, pp. 103-105.

[3] Y.J. Cho, S.H. Hwang, and S.O. Park: “Printed antenna with folded nonuniform meander line for 2.4/5 GHz WLAN bands,” Electron. Lett. 2005, 41, (14), pp. 786-788.

[4] J.Y. Jan, and L.C. Tseng: “Small planar monopole antenna with a shorted parasitic inverted-L wire for wireless communications in the 2.4-, 5.2-, and 5.8-GHz bands,”IEEE Trans. Antennas Propag., 2004, 52, (7), pp. 1903-1905.

[5] W.C. Liu: “Wideband dual-frequency double inverted-L CPW-fed monopole antenna for WLAN application,” IEE Proc. Microw. Antennas Propag. 2005, 152, (6), pp. 505-510.

國際替代計量

短路雙生階梯式多輸入多輸出天線設計

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