臺灣博碩士論文加值系統

本篇論文為寬頻天線應用於微波成像探討，本論文分為兩個部分，第一個部分是設計一個寬頻天線應用於全球衛星定位系統(Global Navigation Satellite Systems，GNSS)，由於全球衛星定位系統屬於衛星通訊上的應用，因此使用的天線必須為圓形極化天線，本論文提出了電磁偶極圓形極化天線，電磁偶極天線的優點在於它有很寬的頻寬及很穩定的增益還有就是天線之間的隔離度很好，另外也提出了使用金屬盒的辦法，這樣可以讓背向輻射變低，缺點就是結構變的比較複雜難以實現。
第二部分是微波成像，其工作原理為發射天線對待測的物體發射微波，然後接收天線透過待測物體外部的量測值或者是介電系數的分布來重構待測物體的形狀，以達到成像。這裡並沒有將第一部分所設計的天線加入，原因是成像的品質，最有直接關係的就是解析度，解析度又跟天線的頻率高低有關係，天線的頻率越高，解析度就越好，但是如果為了提升解析度而讓天線頻率增加，反而會讓訊雜比變差，因為訊號雜訊比會影響到對比度的好壞。本論文將利用模擬軟體分析從金屬球的成像到模擬人頭裡血管的成像等，實作部分會利用陣列天線當作接收面，利用接收面接收到的資料去做運算來達到不同切面的成像。

The circular polarized antenna design is on demand for the global position system (GPS) which is one of the global communication applications. This paper investigates a broadband circular polarized antenna design for microwave imaging applications. Firstly, the novel design approach of the circular polarized dipole antenna is proposed to have features of very wide bandwidth and very stable gain by using a metal box instead of the method by changing the radiation pattern. However, the proposed method makes fabrication and construction more complicated.
Subsequently, employing the proposed broadband circular polarized antenna design for microwave imaging is discussed in details. The operating principle of microwave imaging is a process through applying antenna to transmit the microwave signal upon the objective target, and then the signal is reflected by the target back to the receiving antenna for image data processing. The major factor affecting the imaging quality directly is the resolution which is related to the frequency of the antenna. The higher the frequency was, the better the resolution got. Nevertheless, for the reason of the signal-to-noise ratio affects the contrast, the signal-to-noise ratio will deteriorate by increasing the frequency. In this paper, the simulation software is developed to analyze the imaging processing of the objects, such as metal sphere and the blood vessel in the simulated human head. After that, the imaging of the objective target can be obtained by using the data from the receiving echo signals which are the reflected signal from the surface of the target.

摘要.............................I
Abstract.........................II
目錄.............................III
圖目錄...........................IX
表目錄...........................XII
第一章 緒論.....................1
1.1 前言.........................1
1.2 研究動機.....................1
1.3 論文架構.....................3
第二章 基本理論.................4
2.1 電磁偶極天線.................4
2.2 威金森功率分配器.............6
2.3 天線軸比....................7
第三章 天線結構模擬與分析........8
3.1威金森功率分配器與相移器........8
3.2電磁偶極天線結構與分析.........12
3.3 電磁偶極圓極化天線............17
第四章 微波成像基本理論...........23
4.1 合成孔徑雷達原理...............23
4.2 成像原理探討..................24
第五章 微波影像量測................27
5.1 成像模擬結果....................27
5.2 儀器介紹........................37
5.3接收天線實測結果..................39
5.4量測方法及環境介紹................42
5.5微波影像實驗結果..................45
第六章 結論與未來展望...............54
參考文獻.............................55

[1]Y. X. Sun and K. W. Leung, “Dual-band and wideband dual-polarized cylindrical dielectric resonator antennas,” IEEE Antennas and Wireless Propagation Letters, vol. 12, 2013, pp. 384–387.
[2]M. Li and K. M. Luk, “A wideband dual-polarized antenna with very
low back radiation,” Asia-Pacific Microwave Conference, December 4–7 2012, pp. 61–63.
[3]K. M. Luk and B. Wu, “The magnetoelectric dipole, a wideband antenna for base stations in mobile communications,” Proceedings of the IEEE,vol. 100, no. 7, July 2012, pp. 2297–2307.
[4]Mingjian Li and Kwai-Man Luk, “Wideband Magnetoelectric Dipole
Antennas With Dual Polarization and Circular Polarization,” Proceedings of the IEEE, Vol. 57, No. 1, February 2015,pp.110-119
[5]Z. Y. Zhang, Y. X. Guo, L. C. Ong, and M. Y. W. Chia, “A new wideban dplanar balun on a single-layer PCB,” IEEE Microwave and Wireless Comp. Lett., vol. 15, no. 6, pp. 416–418, Jun. 2005.
[6]Yong-Xin Guo, Chi-LunMak, Kwai-Man Luk, “Analysis and Design of L-Probe Proximity Fed-Patch Antennas,” IEEE Trans. Antennas Propag., vol. 49, NO. 2, Feb. 2001
[7]鄭柏煒, Broadband Wide-beam Circular Polarization Antenna for Global Navigation Satellite Systems Application,亞東技術學院資訊與通訊工程碩士班,2015

[8]K. M. Mak and K. M. Luk, “A circularly polarized antenna with wide
axial ratio beamwidth,” IEEE Trans. Antennas and Propagation, vol. AP-57, 10, October 2009, pp. 3309–3312.
[9]Y. X. Guo, K. W. Khoo, and L. C. Ong, “Wideband dual-polarized
patch antenna with broadband baluns,” IEEE Trans. Antennas and
Propagation, vol. AP-55, no. 1, January 2007, pp. 78–83.
[10]Y.L. Qi, X.L. Yang, W.X. Tan, Y.P. Wang, W. Hong, "Reserch on the Microwave Snapshot Imaging Radar Based on antenna array", IET International Radar Conference, 2013..
[11]Ho-Chi Chu, “Wideband RCS Reduction Using A Composite Impedance Surface”, 碩士論文, 國立交通大學電信工程研究所, 2010.
[12]蔡曜駿, The Study of Microwave Imaging and It’s Performance Improvement, 亞東技術學院資訊與通訊工程碩士班,2014
[13]蔡尚岳, 趙品尊, 林益如, “醫療影像之技術發展趨勢”, 台灣科技發展政策報導, 第三期, 2009.