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標題: | 最佳化印刷式超寬頻平衡器與雙極化自我互補對數週期天線之整合設計 Integrated Design of Optimized Printed UWB Balun and Dual-Polarized Self-Complementary Log-Periodic Antenna |
作者: | Keng-Chih Lin 林耿摯 |
指導教授: | 林怡成(Yi-Cheng Lin) |
關鍵字: | 天線饋入,平衡器,雙極化天線,對數週期天線,自我互補天線,超寬頻天線, Antenna feeds,balun,dual-polarized antennas,log-periodic antennas,self-complementary antennas,ultra wideband antennas, |
出版年 : | 2013 |
學位: | 博士 |
摘要: | 本論文之主題係提出一個基於印刷式超寬頻補償式平衡器的最佳化設計,與一雙極化自我互補型對數週期天線之整合設計。在平衡器的基礎分析中,前人所提出的頻寬拓展最佳化設計方法,最大頻寬和最佳阻抗匹配總是無法兼得。我們提出一個新的設計原則,不僅可以在中心頻具有最佳之阻抗匹配,且同時擁有比傳統方法更好的頻寬表現。本論文提出一補償式平衡器的頻寬最佳化設計方法,並搭配一套參數設計公式,除了可應用於不同阻抗的平衡端負載需求,也可適用於任何返回損失的規格要求,而不侷限於10 dB的標準。理論分析與模型推導之外,本論文也實際以兩種單一平衡器原型的實作來驗證理論的準確性,所量測的印刷式平衡器的頻寬比可拓展到15:1。
在雙極化自我互補型對數週期天線的整合設計方面,本論文根據所提出的最佳化設計方法,設計出雙平衡器架構,作為連接雙極化超寬頻對數週期天線的饋入電路,並且以一平面自我互補對數週期天線結構,與此雙平衡器做整合設計,實現一完整的印刷式超寬頻雙極化自我互補對數週期天線。此天線擁有以下特色:(1)雙埠饋入對應超寬頻雙線性極化的輻射特性,操作頻寬涵蓋1 GHz∼7.5 GHz。(2)平面式設計,製作上適用於低成本之印刷電路板製程。(3)中心垂直饋入,易於與外部電路和射頻系統整合。受惠於雙平衡器的高平衡度特性,整合後的天線輻射場形與天線增益在操作頻段內具有良好的穩定性。隔離度方面,雙平衡器本身具有25 dB以上的埠對埠隔離度,在與天線整合後也仍達到優於20 dB的埠對埠隔離度,最後在輻射場形之表現也達到15 dB以上的交叉極化鑑別度(cross-polarization discrimination)。本研究所有模擬結果與原型實作量測結果皆具有良好的一致性。 This dissertation presents a new approach for the optimal design of printed ultra wideband (UWB) compensated balun and the integrated design with a dual-polarized self-complementary log-periodic antenna (SCLPA). In light of the trade-off between the impedance bandwidth and the impedance matching found within the classic designs, we propose a new approach that may simultaneously perform a perfect matching at the center frequency and a better impedance bandwidth than that of the classic designs. A set of closed-form formula is proposed for the optimal bandwidth design under an arbitrary return loss specification. Additionally, the proposed approach can be applied for the arbitrary terminated condition with various loaded impedance at the balanced port. For verification, we also implement two prototypes of printed compensated balun of different bandwidth ratio. We achieved the bandwidth ratio of 15:1 from the developed printed balun. For the integration design of dual-polarized SCLPA, we design a novel dual-sense (corresponding to the dual polarizations) printed compensated UWB balun, as the feeding network of the dual-polarized SCLPA. The dual-sense balun is designed to integrate with a planar SCLPA structure for a UWB dual-polarized SCLPA module. This antenna module is characterized by the following features: (1) Dual input ports are corresponding to the dual linear polarizations of radiation patterns, respectively. The operational frequency band of each port covers a very wide bandwidth from 1 GHz to 7.5 GHz. (2) The planar design is suitable for the low-cost PCB manufacturing process. (3) Central vertical feed, which may ease the integration with circuits and RF systems. Benefits from the high balance characteristics of the dual-sense balun, the radiation patterns and gain performances of the integrated SCLPA are quite stable over the entire operational bandwidth. Besides, the port-to-port isolations of the dual-sense balun are better than 25 dB, leading to the port-to-port isolation of 20 dB and the cross-polarization discrimination (XPD) of 15 dB. The overall measurement results of the prototype have good agreement with the simulation results. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/17003 |
全文授權: | 未授權 |
顯示於系所單位: | 電信工程學研究所 |
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