直交表用於倒L雙頻天線之設計

淡江大學機構典藏 > 工學院 > 電機工程學系暨研究所 > 學位論文 > Item 987654321/88138

Please use this identifier to cite or link to this item: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/88138

Title:	直交表用於倒L雙頻天線之設計
Other Titles:	Application of orthogonal array for the design of inverted L antenna
Authors:	翁志宏;Weng, Chih-Hung
Contributors:	淡江大學電機工程學系碩士班李慶烈;Li, Ching-Lieh
Keywords:	平面天線;倒L天線;雙頻;田口法;直交表;planar antenna;ILA;dual band;Taguchi method
Date:	2012
Issue Date:	2013-04-13 12:02:29 (UTC+8)
Abstract:	本論文探討藉由直交表(Orthogonal Array, OA)的使用以進行偏移饋入的倒L天線設計及其延伸。目標設定在設計一種平面式的雙頻天線，期待能在有限且少量次數的迭代次數內，使天線結構達到我們所要求之優化設計。藉由偏移饋入(offset-fed)的結構以及耦合strip的引進而形成雙頻天線，進一步衍伸出非對稱的T型結構則可以加大低頻段的頻寬，目標在設計一符合WLAN雙頻頻段(2.4GHz、5.2GHz及5.8GHz)的天線，實務上則以IPEX同軸線作為饋入線材。本論文中的天線採用厚0.8mm 的FR4 印刷電路板(相對介電係數為4.4、Dielectric Loss Tangent 為0.02)來進行模擬分析與設計與設計，並進行如下的優化設計、並和實作結果相驗證。為了完成上述的創新迭代設計過程，首先得根據具耦合strip的偏移饋入(offset-fed)的倒L結構，選定設計/調配之結構參數以及參數之位準(level)，建立一個適當之直交表；之後再以電磁模擬軟體執行直交表上的部份因子實驗，進行少量且有限次數的迭代；依據模擬數據來計算不同因子實驗之適應值，以進行天線參數之優化，目的在測試本論文得設計方法是否能在進行少量且有限次數的迭代之後，滿足預先規畫的頻段規格要求。在本研究中，我們分別測試了只使用一階段(五次或十次迭代) 的搜尋方式，以及使用兩階段(每階段各五次迭代)的搜尋方式來運用田口最佳化法以進行有限次數的搜尋，模擬結果顯示應用連續直交表的設計方法被證明具有快速收斂的特性，設計者可依照此方法明確且快速地搜尋到符合期望輸出的參數組合。 In this thesis, the application of Orthogonal Array (OA) to design an offset-fed inverted L antenna through a novel iterative procedure is investigated. The objective is to design a planar dual-band antenna. A coaxial-fed inverted L antenna structure and its extension is optimized through the proposed novel procedure. It is expected that within a certain limited small iterations the S11 characteristics of the antenna can satisfy the required specification. The offset-fed inverted L antenna associated with a coupled strip exhibit dual-band structure. Moreover, it is found that the bandwidth at the low band can be widened by suitable extending the inverted L shape to un-symmetric T shape. The goal is to design a dual-band antenna with frequency range covering the WLAN (802.11a/b/g/n) application. The antenna is fed by a IPEX coaxial line, in practice. The antenna concerned is assumed to reside on an FR4 substrate (of thickness of 0.8mm, and with relative dielectric constant of 4.4 and loss tangent~0.02), and. For the above conditions, the antenna simulation and the iteratively optimized design are carried out, and finally the novel antennas are fabricated and verified by measurement. For the novel iterative design procedure, the parameters of the inverted L antenna with coupled strip are first choice, and their ranges are suitably set, then a corresponding OA can be established. Next, the fractional factorial experiments of the OA are carried out by using the commercial electromagnetic simulation software. Based on the simulation results, the fitness of the fractional factorial experiments are calculated such that the limited small number of iterations is conducted to optimize the antenna parameters. The objective is to test that whether the proposed novel antenna design procedure work to have the convergent antenna meet the pre-set frequency requirement or not, As compared to other design method, the most important feature of the proposed novel method is the utilization of the OA, which exhibits the uniformity for the occurrence of each level of the parameters. The inclusion of OA is expected to accelerate the design process, reduce the search time. When the OA is combined with the range reduction technique, it is found quite suitable to serve as an alternative for antenna design. In this study, we test two kinds of design procedure with one phase and two phases, respectively, in order to utilize OAs within a limited number of iterations. For the one-phase case, 5 iterations or 10 iterations are tested, while for the two-phase case, there are 5 iterations for each phase. The test results show that the proposed novel methods utilizing consecutive OAs are able to obtain good results in a fast way.
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