臺灣博碩士論文加值系統

耦合器在為波電路中是一個非常重要的元件。傳統微帶線枝幹耦合器是由四分之一波長傳輸線組成。其功用為功率合成器或功率分配器使用，傳統枝幹耦合器的特點為輸入端和輸出端功率相等，相位差90°，可應運於平衡式放大器或混頻器來使用。隨著技術的進步，通信系統近年來迅速發展。目前，為了配合產品體積小，電路尺寸減小且要低成本製造，這些需求都集中在現代無線通信系統的組件上。
在該研究中，新型微小化枝幹耦合器是利用等差架構及彎折的架構來設計，沒有任何外接元件，孔洞和接合線。而且，推導了等差結構和折疊結構的設計方程，來避免內部枝幹重疊的問題產生，並設計及製作在FR4板材，工作頻率為900 MHz。另外，在與相同工作頻率的傳統耦合器相比，等差結構和折疊結構耦合器的電路面積減小了84.2％和85.1％。所提出的耦合器能容易與無線通信系統整合。

The conventional branch-line coupler is consisted of four quarter wavelength transmission lines. Coupler devices are used to divide power and generate phase difference in radio transceivers. Conventional 90° hybrid couplers are implemented in balanced amplifier or mixer circuit design. With advancement in technology, communication systems have rapidly evolved in recent years. Currently, all cost-reduction efforts, including size reduction and low-cost fabrication, are focused on the components of modern wireless communication systems.
In the study, the novel compact coupler was designed with equal different structure and folding structure without any implementation of lumped elements, via-holes, and bonding wires. However, the use of unoccupied area of coupler interiors reveals overlap problems. The design equations of the equal difference structure and folding structure were derived, and a compact branch-line coupler was designed and assembled on FR4 substrate with a 900 MHz operating frequency. Additionally, the circuit area of the equal difference structure and folding structure couplers achieves a size reduction of 84.2% and 85.1% compared with that of a conventional coupler at the same operating frequency. The proposed coupler was successfully designed for easy integration with modern wireless communication systems.

Chapter 1 Introduction 9
Chapter 2 Introduction of Microstrip Lines 13
2-1 Introduction of microstrip lines 13
2-2 Characteristics of the microstrip line 20
Chapter 3 Introduction Branch Line Coupler 23
3-1 Conventional branch-line coupler 23
3-2 Several design techniques reduce the coupler size 25
3-3 T-shaped structure 31
3-4 Circuit size reduction with equal different structure 37
Chapter 4 Compact Branch-Line Coupler Designed and Fabricated 40
4-1 Compact coupler with equal different structure design 40
4-2 The circuit fabricated and simulation of equal different structure 43
4-4 Circuit design of the novel fold structure 45
4-5 Circuit fabrication and simulation of novel fold structure 49
Chapter 5 Novel Compact Coupler of Measured Results 51
5-1 Measured result of equal different structure 51
5-2 Measured results of novel folding structure 53
Chapter 6 Conclusion 55
6-1 Conclusion with equal different structure 55
Reference 57

[1] P. Kurgan, and M. Kitlinski, Novel doubly perforated broadband microstrip branch-line couplers, Microwave Opt Tech Lett 51 (2009), 2149–2152.
[2] H.-Y. Zeng, G.-M. Wang, Z.-W. Yu, X.-K. Zhang, and T.-P. Li, Miniaturization of Branch-Line Coupler Using Composite Right/ Left-Handed Transmission Lines with Novel Meande r-shaped-slots CSSRR, Radioengineering 21 (2012), 606–610.
[3] H.-X. Xu, G.-M. Wang, and C.-X. Zhang, Compact design of branch-line coupler based on CRLH TL combined with fractal shaped geometry, 2010 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 2010, pp. 1658–1661
[4] Kae-Oh Sun, Sung-Jin Ho, Chih-Chuan Yen and D. van der Weide, "A compact branch-line coupler using discontinuous microstrip lines," in IEEE Microwave and Wireless Components Letters, vol. 15, no. 8, pp. 519-520, Aug. 2005.
[5] S. C. Jung, R. Negra and F. M. Ghannouchi, "A Design Methodology for Miniaturized 3-dB Branch-Line Hybrid Couplers Using Distributed Capacitors Printed in the Inner Area," in IEEE Transactions on Microwave Theory and Techniques, vol. 56, no. 12, pp. 2950-2953, Dec. 2008.
[6] J. Wang, B. Z. Wang, Y. X. Guo, L. C. Ong and S. Xiao, "A Compact Slow-Wave Microstrip Branch-Line Coupler With High Performance," in IEEE Microwave and Wireless Components Letters, vol. 17, no. 7, pp. 501-503, July 2007.
[7] C. W. Tang, M. G. Chen and C. H. Tsai, "Miniaturization of Microstrip Branch-Line Coupler With Dual Transmission Lines," in IEEE Microwave and Wireless Components Letters, vol. 18, no. 3, pp. 185-187, March 2008.
[8] S. R. Best, "A comparison of the resonant properties of small space-filling fractal antennas", IEEE Antennas Wireless Propag. Lett., vol. 2, pp. 197-200, 2003
[9] 郭仁財編譯，David M. Pozar原著。“微波工程(第二版)” 高立圖書有限公司，民國90年。
[10] 翁敏航編著。“倍頻被動元件設計”東華書局，民國95年。
[11] M. Caulton, B. Hershenov, S. P. Knight and R. E. DeBrecht, "Status of Lumped Elements in Microwave Integrated Circuits - Present and Future," in IEEE Transactions on Microwave Theory and Techniques, vol. 19, no. 7, pp. 588-599, Jul. 1971.
[12] R. K. Gupta and W. J. Getsinger, "Quasi-Lumped-Element 3- and 4-Port Networks for MIC and MMIC Applications," 1984 IEEE MTT-S International Microwave Symposium Digest, San Francisco, CA, USA, 1984, pp. 409-411.
[13] Yi-Chyun Chiang and Chong-Yi Chen, "Design of a wide-band lumped-element 3-dB quadrature coupler," in IEEE Transactions on Microwave Theory and Techniques, vol. 49, no. 3, pp. 476-479, March 2001.
[14] T. Hirota, A. Minakawa and M. Muraguchi, "Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's," in IEEE Transactions on Microwave Theory and Techniques, vol. 38, no. 3, pp. 270-275, March 1990.
[15] K. W. Eccleston and S. H. M. Ong, "Compact planar microstripline branch-line and rat-race couplers," in IEEE Transactions on Microwave Theory and Techniques, vol. 51, no. 10, pp. 2119-2125, Oct. 2003.
[16] Shry-Sann Liao, Pou-Tou Sun, Nien-Chung Chin and Jen-Tee Peng, "A novel compact-size branch-line coupler," in IEEE Microwave and Wireless Components Letters, vol. 15, no. 9, pp. 588-590, Sept. 2005.
[17] C. Tang and M. Chen, "Synthesizing Microstrip Branch-Line Couplers With Predetermined Compact Size and Bandwidth," in IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 9, pp. 1926-1934, Sept. 2007.
[18] Huaming Wang, Xueguang Liu, Wenfeng Cai and Hongfang Cao, "Design and realization of a new compact branch-line coupler using defected ground structure," 2008 9th International Conference on Solid-State and Integrated-Circuit Technology, Beijing, 2008, pp. 1376-1379.
[19] Y O Elhiwaris, M & abdul rahim, Sharul & Chude Okonkwo, Uche & Jizat, N & Jamlos, Mohd. (2011). Miniaturized size branch line coupler using open stubs with high-low impedances. Progress In Electromagnetics Research Letters. 23. 10.2528/PIERL11022306.