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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/94547


    Title: 應用最佳化法則在不同陣列天線高度下降低路徑耗損
    Other Titles: Outdoor path loss reduction for different antenna arrays with various height by optimization methods
    Authors: 洪啟捷;Hung, Chi-Jie
    Contributors: 淡江大學電機工程學系碩士班
    嚴雨田
    Keywords: 射線追蹤法;基因演算法;動態差異演算法;天線高度;路徑耗損;SBR/Image method;outdoor environments;antenna patterns;Path loss;Genetic Algorithm;dynamic differential evolution algorithm;Height.
    Date: 2013
    Issue Date: 2014-01-23 14:45:30 (UTC+8)
    Abstract: 在本論文中所呈現的是戶外無線通訊系統的通道特性分析。在戶外的環境中,有許多阻擋物會干擾和減弱接收訊號的功率,例如車輛樹木和建築物高低。所以我們的目的是要分析與了解戶外無線通訊系統的通道特性。 我們考慮了兩種不同形式的傳送端天線陣列與六種傳送端天線高度來評估戶外環境中的路徑損失。藉由使用遺傳基因演算法與動態差異演算法兩種演算法,來改善陣列天線的天線場型,使得無線通訊訊號傳輸具有良好的指向性並減少環境的多路徑干擾產生的路徑損失。
    在本文中,吾人利用遺傳基因演算法與動態差異演算法來把具有指向性的天線陣列加入戶外環境裡,用射線彈跳-影像法(SRB-image method)來模擬傳播通道,進而分別分析兩種演算法如何改良天線場型,使得所需區域的路徑損失(Path Loss)下降更多,並減少基地台上的功率浪費,並比較兩種演算法在兩種不同形狀的天線陣列和六種傳送端高度下的各項優缺點。
    研究結果顯示,發射天線越高的情況之下,路徑耗損越少,因為當傳送端天線越高時,在接收端部分,會有更高的機率接收到藉由反射與繞射的訊號,其中動態差異演算法所模擬出的數值結果皆優於遺傳基因演算法,而環型天線陣列所模擬出來的數值結果又優於叉型天線陣列。模擬的數值結果,可以提供工程師,或是使用者,在設計天線或是傳送端的擺放,甚至是使用上,做為參考。
    In this paper, we use the shooting and bouncing ray/image (SBR/Image) method to compute the path loss for different outdoor environments in the residential area. Six kind of transmitting antenna heights are concerned and two types of antenna arrays such as Cross type and circular type arrays are used in the base station. Their corresponding path loss on several routes of the outdoor environment are calculated. Moreover, the genetic algorithm (GA) and dynamic differential evolution algorithm (DDE) are employed to optimize the excitation voltages and phases for these antenna arrays to reduce the path loss. By the obtained antenna patterns, we can know the route with the lowest path loss; meanwhile, transmission power using this route in the base station can be reduced. Numerical results show that the performance in reduction of path loss by DDE algorithm is better than that by GA for these antenna arrays. Also the path loss of the higher transmitting antenna is better than lower one. Because there are more opportunities to get reflection and diffraction wave when transmitting antenna raised that decrease the path loss. The investigated results can help communication engineers improve their planning and design of outdoor communication system.
    Appears in Collections:[電機工程學系暨研究所] 學位論文

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