在現代通信系統，無線服務的需求不斷增加，帶動了通信系統，支持多標準的操作需要。 雙波段或多波段操作幾乎都是必要的，能夠提供這些操作的微波器件已成為減小尺寸和降低成本有吸引力的解決方案。 / 分支線耦合器是用於微波和毫米波應用的最流行的無源電路之一。它們通常用於平衡放大器和混頻器去實現良好的回波損耗以及隔離。其中一個至關重要的部份是設計一個可以靈活作多波段分配的分支線耦合器。 / 傳統上，完全平面的實施，雙波段分支線耦合器可以通過短截線，階梯阻抗線，耦合線等不同的分佈式結構實現。不同的設計方案已在這幾年來出現。窄帶操作和複雜的電路設計，是以前的設計的主要缺點。雖然，在理論上，多節技術可以拓寬帶寬，但它的主要缺點是電路的面積變大了及使用極端低/高傳輸線阻抗。因此，它不是一個大量和低成本生產的解決方案。 / 在這項研究中，設計了全新的並增強了性能的雙波段分支線耦合器(零分貝和三分貝的功率分裂)。這些設計能在兩個指定的頻帶有不平等的工作帶寛。通過正確選擇雙頻四分之一波長阻抗變換器的電氣長度和線路阻抗，傳輸相位斜率將能夠被控制並給出帶寬不對稱的特點，其性能可以進一步擴展，涵蓋了廣泛的應用。 / 以上所有設計都只需要單層線路版的制作及可實現的傳輸線阻抗。應用奇/偶模式分析所給出設計公式。這些設計具有低損耗，佈局靈活，緊密的尺寸大小的特性。這些設計己經使用標準微帶的結構實現其特點，其結果得到了實驗結果的進一步驗證。分支線耦合器只需要更小的節數就能實現相同的性能。 / In modern communication systems, the increasing demand for wireless services has driven the need for communication systems that support multi-standard operations. Dual-/Multi- band operation is almost a necessity and the adoption of microwave multi-band devices has become an attractive solution towards size and cost reduction of RF frontend designs. / Branch-line coupler is one of the most popular passive circuits used for microwave and millimeter-wave applications. They are commonly used in balanced amplifiers, phase-shifter, mixer and frequency multipliers for achieving good return loss, as well as isolation. It is therefore essential to have a branch-line coupler with multi-band operation. / Traditionally, for fully planar implementation, the construction of dual-band branch-line couplers are usually accomplished by distributed structures based upon shunt-stub, stepped-impedance line, coupled line etc. Narrow-band operation and circuit complexity are the major drawbacks for these previous designs. Although, in theory, the available bandwidth may be broadened by multi-section configurations, its major tradeoffs are the enlarged circuit size as well as the extreme line dimensions involved. Therefore, it is not preferable to mass and low cost production. / In this research, advanced designs of dual-band branch-line coupler (0 dB and 3 dB power splitting) with enhanced performances are presented. By proper selection of the number of sections, electrical lengths and line impedances of appropriate branch-lines of the coupler, its performance can be further extended to cover a wide range of applications. / All the proposed circuits require only single-layer fabrication and realizable line impedance. Closed form design formulas are made available by the application of even/odd- mode formulation. They feature low loss, flexible layout and compact size. The designs have been implemented and characterized using standard microstrip, and verified experimentally. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yeung, Sung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 92-95). / Abstracts also in Chinese. / Abstract --- p.ii / 摘要 --- p.iii / Acknowledgement --- p.iv / Table of Content --- p.v / Lists of Figures --- p.viii / Lists of Tables --- p.xii / Chapter Chapter 1 --- : Introduction --- p.1 / Chapter 1.1 --- Research Motivation and Objective --- p.1 / Chapter 1.2 --- Original Contribution --- p.3 / Chapter 1.3 --- Research Approach, Assumptions and Limitations --- p.4 / Chapter 1.4 --- Overview of the Thesis Organization --- p.5 / Chapter Chapter 2 --- : Review of Microwave Coupler Design --- p.6 / Chapter 2.1 --- Coupler Design Fundamental --- p.6 / Chapter 2.1.1 --- Coupler Design with Equal Power Splitting --- p.7 / Chapter 2.1.2 --- Coupler Design with Unequal Power Splitting --- p.12 / Chapter 2.1.3 --- 0-dB Coupler or Crossover --- p.16 / Chapter 2.1.4 --- Coupler Design with Size Miniaturization --- p.18 / Chapter 2.1.5 --- Wide Band Coupler Design --- p.21 / Chapter 2.2 --- Dual-Band and Multi-Band Branch-line Coupler --- p.25 / Chapter 2.2.1 --- Dual-Band Couplers Based on Composite Right/Left-Handed Transmission Line --- p.25 / Chapter 2.2.2 --- Dual-Band Couplers with Shunt Stubs --- p.28 / Chapter 2.2.3 --- Dual-Band Coupler Based on Stepped-Impedance-Stub-Line --- p.30 / Chapter 2.2.4 --- Dual-Band Coupler with Port Extensions --- p.33 / Chapter 2.2.5 --- Tri-Band Coupler Based on Matching Network --- p.35 / Chapter 2.2.6 --- Multi-passband Branch-line Coupler Design --- p.37 / Chapter 2.3 --- Summary --- p.39 / Chapter Chapter 3 --- : A Novel Dual-band 0-dB Branch-line Coupler Design --- p.40 / Chapter 3.1 --- Proposed Circuit --- p.40 / Chapter 3.2 --- Analysis of Single-band 0-dB Branch-line Coupler --- p.43 / Chapter 3.3 --- Single- to Dual-band Conversion --- p.52 / Chapter 3.4 --- Experimental Results --- p.55 / Chapter 3.5 --- Summary --- p.58 / Chapter Chapter 4 --- : A Novel Dual-band 3-dB Branch-line Coupler with Unequal Bandwidth --- p.59 / Chapter 4.1 --- Proposed Dual-band Impedance Transformer: --- p.59 / Chapter 4.2 --- Single-band 3-dB Coupler Design --- p.65 / Chapter 4.3 --- Dual-band 3-dB Coupler Design --- p.70 / Chapter 4.4 --- Experimental Results --- p.76 / Chapter 4.4.1 --- Equal bandwidth design --- p.76 / Chapter 4.4.2 --- Unequal bandwidth design --- p.78 / Chapter 4.5 --- Summary --- p.81 / Chapter Chapter 5 --- : A Novel Dual-band 0-dB Branch-line Coupler Design with Unequal Bandwidth --- p.82 / Chapter 5.1 --- Proposed Circuit --- p.82 / Chapter 5.2 --- Analysis and Formulation --- p.84 / Chapter 5.3 --- Simulation Results --- p.85 / Chapter 5.4 --- Experimental Results --- p.87 / Chapter 5.5 --- Summary --- p.89 / Chapter Chapter 6 --- : Conclusion and Recommendation for Future Work --- p.90 / Chapter 6.1 --- Conclusion --- p.90 / Chapter 6.2 --- Recommendation for future work --- p.91 / References --- p.92 / Author’s Publications --- p.96 / Chapter Appendix 1: --- Brief Summary of Design Approaches of Hybrids Couplers --- p.97 / Chapter Appendix 2: --- Transformation between S- and ABCD- parameters for two-port network --- p.99
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328801 |
| Date | January 2012 |
| Contributors | Yeung, Sung., Chinese University of Hong Kong Graduate School. Division of Electronic Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xii, 99 leaves) : ill. (some col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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