林怡成Lin, Yi-Cheng臺灣大學:電信工程學研究所吳翰揚Wu, Han-YangHan-YangWu2010-07-012018-07-052010-07-012018-07-052009U0001-1707200914105300http://ntur.lib.ntu.edu.tw//handle/246246/188326對數週期偶極天線屬於非頻變天線的一種，具有線性極化與平穩的增益場型（Gain Pattern）等特性，非常適合應用在EMI或天線的量測上。傳統的對數週期偶極天線是由金屬圓柱所組成，並用同軸電纜來饋入，造成天線的體積及重量都較大，且難以製作等缺點。近年來，有文獻提出運用平面印刷電路板技術製作的對數週期偶極天線，然而，由於這些設計並未有效地遮蔽饋入線的輻射，以及並未運用平衡機制來饋入，其交叉極化的輻射量往往很高。在本論文中，我們運用印刷電路板技術，設計出兩款以平衡器（Balun）饋入之對數週期偶極天線。在前半部份，我們成功地在雙層印刷電路板上設計出一個頻寬為0.66~5.71GHz的平衡器，且其兩個輸出端之能量差在1.0dB以內，相位差則在10度以內。在後半部份，我們整合平衡器與對數週期偶極天線的設計，並同樣將之實現在雙層印刷電路板上。我們所提出的兩款天線設計，其頻寬分別為0.8~3.2GHz與0.8~6.0GHz，反射係數的模擬與量測結果非常吻合。此外，全頻段量測之同極化（Co-Pol.）正向增益介於0dBi至6dBi之間，表現非常平穩，交叉極化隔離度（Cross-Pol. Isolation）則約為20dB。The log-periodic dipole antenna (LPDA) is categorized as a frequency independent antenna with linear polarization and stable gain patterns; therefore it is suitable for the source antenna in EMI/Antenna measurement. Traditional LPDA is made of metal cylinders fed by coaxial cables making the antenna heavy and difficult to fabricate. Planar printed circuit board (PCB) LPDA was proposed recently; however, its unshielded and unbalanced feeding line may cause the cross-polarization too high to be used for practical applications. In this thesis, we propose a balun-based feeding scheme integrated with the planar LPDA using the multi-layered PCB technology. In the first half of the thesis, we design a Marchand balun in a multi-layered PCB with measured amplitude and phase balance within 1.0 dB and 10 degrees respectively over the 0.66~5.71 GHz band. In the second half of this thesis, we integrate the developed balun with the planar LPDA on the same PCB. Two designs are demonstrated for the 0.8~3.2 GHz and 0.8~6.0 GHz bands respectively. Both designs show good results in the wideband impedance matching, stable broadside gain range 0~6 dBi, and the highly isolated cross-polarization of 20 dB over the entire band.第一章　簡介……………………………………………………………1.1 研究動機……………………………………………………………1.2 章節概要……………………………………………………………3二章　對數週期偶極天線之基礎研究與討論………………………4.1 前言…………………………………………………………………4.2 設計參數與基本概念………………………………………………4.3 各類型對數週期偶極天線…………………………………………11.4 對數週期偶極天線之相位中心探討………………………………15三章　平面化超寬頻平衡器實現在PCB之研究.…………………16.1 前言…………………………………………………………………16.2 平面化平衡器之文獻檢索…………………………………………16.3 立體平衡器原理探討………………………………………………20.4 以ADS進行平衡器之主要參數分析………………………………22.5 平面化超寬頻平衡器之設計………………………………………25.5.1平衡器結構………………………………………………………25.5.2 平衡器之模擬與量測結果………………………………………28四章　以平衡器饋入之對數週期偶極天線之設計與實作………31.1 前言…………………………………………………………………31.2 傳統型平面化對數週期偶極天線…………………………………31.2.1 天線結構…………………………………………………………31.2.2 天線之模擬結果…………………………………………………34.3 平衡器之設計與模擬結果…………………………………………40.3.1 平衡器結構………………………………………………………40.3.2 平衡器之模擬結果………………………………………………43.4 以平衡器饋入之對數週期偶極天線………………………………46.4.1 天線結構…………………………………………………………46.4.2 天線之模擬與討論………………………………………………49.5 以挖槽破壞天線橫向共振模態……………………………………56.5.1 天線結構…………………………………………………………56.5.2 天線之模擬與量測結果…………………………………………59.6 超寬頻版以平衡器饋入之對數週期偶極天線……………………65.6.1 平衡器結構………………………………………………………65.6.2 平衡器之模擬結果………………………………………………68.6.3 天線結構…………………………………………………………71.6.4 天線之模擬與量測結果…………………………………………74五章　結論…………………………………………………………83考文獻………………………………………………………………854907867 bytesapplication/pdfen-US平衡器交叉極化隔離對數週期偶極天線平面化天線寬頻Baluncross-polarization isolationLPDA, planar antennabroadbandthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/188326/1/ntu-98-R96942081-1.pdf