近半个世纪来，大量精力致力于研究针对满足不同需求的滤波器综合设计理论。对基于解析方法的滤波器综合设计理论的需求，源源不断的推动着这个课题的研究与发展。传统滤波器综合理论假设滤波器网络两端口终端阻抗相同并且均为不随频率变化的纯实阻抗，该假设等效于认为滤波器两端匹配到具有相同特征阻抗的无耗传输线。但对于一些实际应用，例如多工器中信道滤波器的设计，滤波器的其中一个端口需要匹配到随频率变换的复阻抗 。本篇论文提出了一种适用于广义切比雪夫带通滤波器复阻抗匹配的解析综合方法用于设计一端匹配负载为频率变换的复阻抗而另一端匹配负载为常数实阻抗的滤波器。该方法以功率波再归一化理论为依据并假设：（1） 指定的传输零点不变 （2）反射零点始终纯虚数轴上。本论文通过端口参考阻抗的再归一化，推导出定义滤波器在不同参考阻抗的散射参数的特征多项式之间的三个关系并证在保证网络可实现性的前提下该关系只能通过一个理想的滤波器电路加上一段适合长度的位于滤波器与复阻抗之间的传输线来满足。设计匹配复阻抗的滤波器网络的关键在于保证电路的可实现性的前提下最大程度满足匹配条件。 本篇论文证明了为满足上述要求，引入一段最优长度的传输线的必要性。从在一定频率范围内最大限度匹配复阻抗的角度考虑，引入的传输线长度能够最优确定。论文中所提出的解析且灵活的设计方法可应用于多工器或双工器中信道滤波器的设计。通过具体的设计实例与全波软件的仿真，该方法的可行性得到了验证。 / A great deal of effort has been devoted to the synthesis of microwave filters with required characteristic over the past half century. The driving force to this subject is the demand of analytical solution that facilitates various filter design requirements. Conventional filter synthesis approach assumes the termination impedance of a filter network at both ports is a real constant matched load, which is equivalent to a matched transmission line with same characteristic impedance. But for practical applications such as designing a channel filter of a multiplexer, the filter is required to match a frequency variant complex load at one port. This thesis presents an analytical approach to the synthesis of a general Chebyshev filter that matches to a frequency variant complex load at one port and a real constant load at the other port based on power wave renormalization theory under two practical assumptions: (1) the prescribed transmission zeros are stationary; and (2) the reflection zeros are located along imaginary axis. Three necessary conditions that stipulate the characteristic polynomials associated to the filter are derived through renormalization of the load reference impedances. It has been shown that these three conditions can only be satisfied by an ideal filter circuit model separated by a piece of transmission line from the complex load. The key issues in the synthesis approach are to enforce the realizability conditions of a filter network and to match the complex load with a best effort. For this purpose, it is proved that a section of transmission line with an optimal length must be inserted between the filter network and the complex load. The length of the transmission line will be optimally designed in the sense that the designed filter will best match to the complex load over a given frequency range. The proposed method offers a deterministic yet flexible way for optimally designing a diplexer or a multiplexer with a realistic loading effect. The effectiveness of the method is demonstrated by a number of design examples. / Detailed summary in vernacular field only. / Meng, Huan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 114-116). / Abstracts also in Chinese. / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.v / Table of contents --- p.iv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of Microwave Filters --- p.1 / Chapter 1.2 --- Introduction to Filter Synthesis --- p.3 / Chapter 1.3 --- Contributions of this Thesis --- p.6 / Chapter 1.4 --- Organization of this Thesis --- p.7 / Chapter Chapter 2 --- Review of Direct Filter Synthesis Theory --- p.8 / Chapter 2.1 --- Basic Properties of Characteristic Polynomials --- p.8 / Chapter 2.2 --- Derivation of General Chebyshev Polynomial --- p.15 / Chapter 2.3 --- Analysis of Cross Coupled Resonator Circuit --- p.27 / Chapter 2.4 --- Synthesis of N+2 Transversal Coupling Matrix --- p.35 / Chapter 2.5 --- Reconfiguration of coupling topology --- p.44 / Chapter 2.6 --- Summary --- p.50 / Chapter Chapter 3 --- Direct Synthesis of Microwave Bandpass Filters with A General Loading Effect --- p.51 / Chapter 3.1 --- Introduction --- p.51 / Chapter 3.2 --- Renormalization of Reference Impedance --- p.56 / Chapter 3.3 --- The Direct Synthesis Approach --- p.65 / Chapter 3.4 --- Examples --- p.72 / Chapter 3.4.1 --- Example 1: synthesis with frequency invariant complex load --- p.73 / Chapter 3.4.2 --- Example 2: synthesis with frequency variant complex load --- p.74 / Chapter 3.4.3 --- Example 3: synthesis with a highly reactive complex load --- p.77 / Chapter 3.5 --- Future work --- p.80 / Chapter 3.6 --- Summary --- p.81 / Chapter Chapter 4 --- Design Examples of RF/Microwave Diplexers --- p.82 / Chapter 4.1 --- Introduction --- p.82 / Chapter 4.2 --- Non-contiguous band diplexer design --- p.85 / Chapter 4.2.1 --- Example 1: Diplexer Design Using an H-plane T-Junction --- p.85 / Chapter 4.2.2 --- Example 2: Diplexer Design with a wired Y-junction --- p.92 / Chapter 4.3 --- Discussion on designing a contiguous diplexer --- p.96 / Chapter 4.4 --- Future work --- p.101 / Chapter 4.5 --- Summary --- p.102 / Conclusion --- p.103 / Chapter Appendix I --- : Power Wave Renormalization Theory --- p.104 / Chapter Appendix II --- : Necessary and Sufficient condition of Power Conservation for Objective S --- p.109 / Proof of Sufficiency --- p.109 / Proof of Necessarity --- p.111 / References --- p.114 / Publication --- p.117
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328734 |
| Date | January 2012 |
| Contributors | Meng, Huan., 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 (v, 117 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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