【作者】 孙守家；

【导师】 梁昌洪；

【作者基本信息】 西安电子科技大学 ， 电磁场与微波技术， 2014， 博士

【摘要】 无线通信系统的发展日新月异，新技术如WLan、3G、4G随处可见。新技术的出现给微波器件的设计带来了极大的挑战。滤波器作为最基本的微波器件之一，对其的设计要求更加苛刻，小型化、低插损、高通带选择性、宽阻带等。为了能够使多个通信模式同时工作，宽带和多通带滤波器的使用成为必然。双模谐振器已经被广泛的应用在滤波器的设计中，极大的减小了滤波器的体积，并且具有高性能、低成本的特点。本文从已发表的双模谐振器出发，提出了新型的双模和多模谐振器，对它们的谐振特性和耦合特性进行了详尽的分析，并最终将其应用在了滤波器的设计中。本文的主要工作包括以下几个方面：1.详尽的阐释了奇偶模方法的应用背景及其要解决的核心问题，并且利用它对四种中心枝节加载谐振器的谐振特性进行了分析，并从中发现了新型的双模谐振器，这对本文后面的工作奠定了基础。2.第一次提出了新型的双端短路双模谐振器，通过等效传输线模型对该谐振器的谐振特性及耦合特性进行了详细分析；在宽带滤波器中的应用中，对外部耦合和源和负载耦合的关键参数进行了定量分析，成功的解释了带内极点分布的情况；同时源和负载耦合引入，不仅增强了通带的选择特性，而且还改善了带内波纹特性。另外，通过开路枝节的加载，实现了该谐振器的小型化，并在此基础上设计了双模双通带滤波器。在双通带滤波器的设计中，两个通带的外部耦合是可控的，因此两个通带都拥有非常好的带内阻抗匹配特性。3.在双端短路双模谐振器的基础上，提出了新型的双端短路阶梯阻抗双模谐振器，通过奇偶模分析方法详述了该谐振器的谐振特性，并且给出了该谐振器的设计图；通过控制长度比和阻抗比，第一次用单个双模谐振器实现了三个通带频率都可控的三通带滤波器；在带通滤波器的设计中，选择合适的阻抗比和长度比，使谐振器的一次谐波出现在4.2f0处，从而获得了宽阻带的效果；在双通带和三通带滤波器的设计中，很好的利用了谐振器的电压分布情况，实现了每个通带的外部耦合可控，从而获得了良好的带内阻抗匹配。4.基于枝节加载谐振器，提出了几种新型的三模、四模谐振器，并通过奇偶模分析方法对其谐振特性和耦合特性进行了系统分析；利用提出的谐振器设计了带通、双通带滤波器；一种基于短路枝节加载的四模谐振器设计的双通带滤波器，具有小型化、宽阻带的特性；一种基于短路枝节加载的方环谐振器设计的双通带滤波器，通过源和负载耦合的加载，实现了高隔离度和高选择性的特性；一种基于全短路枝节的三模、四模谐振器用来设计实现了带通滤波器。5.系统的研究了双频阻抗变换器的特性，通过优化的方法将该结构成功的应用在了两个不等阻抗到同一阻抗的变换。阶梯阻抗谐振器(SIRs)作为一种广义概念上的双模谐振器，同样利用奇偶模方法分析了它的谐振特性，并给出了它的设计图。最终，把它作为公共腔，利用双频阻抗变换器对其进行馈电，应用在了双工器和四工器的设计中。在设计过程中，采取了仿真模型参数提取的方法获得SIR在两个频率处的谐振阻抗，利用这种方法设计的双频阻抗变换器更准确、更符合实际。更多还原

【Abstract】 With the rapid development of wireless comunication systems, many newtechnologies can be seen everywhere, such as Wlan,3G and4G. The emergence of newtechnoligies makes the design of microwave components quite challenging. Filter is oneof the most basic microwave components, and its indices has become more and morestringent, such as miniarizaiton, low insertion loss, high passband selectivity andwide-stopband. In order to make multiple communication modes operatingsimultaneously, wideband and multi-band filters are the most popular candidates.Dual-mode resonators, which feature compact size, high performance, and low cost,have been widely used in the filter design. According to the study on the publisheddual-mode resonators, this paper proposed many novel dual-and multi-mode resonators,and their resonance and coupling characteristics have been analyzed in detail. In thispaper, these proposed resonators have been employed to design filters.The author’s works are concluded as follows:1. The application background odd-even-mode method has been studied andemployed to analyze the resonance characteristics of four centrally stub-loadedresontors (CLRs). In this way, a novel dual-mode resonator is observed, which is veryimportant to the latter work in this paper.2. For the first time, a novel short-ended dual-mode resonator has been proposed,and its resonance and coupling characteristics have been given detailed analysis throughthe equivalent transmisson line theorem. For wideband application, an improtantparameter, the external coupling, has been analyzed in quantitative, which successfullydescribes the poles within the passband. Moreover, source-load coupling is introduced,which not only enhance the passband selectivity, but also improves the in-band property.In addition, open-circuit stub is loaded to realize filter miniaturization, and it will beused to design dual-mode dual-band bandpsss filters (BPFs), in the design, the externalcouplings of both passbands can be controlled simultaneously, and good impedancematching can be acheived in each passband.3. A novel short-ended stepped-impedance dual-mode resonator is proposed basedon the short-ended dual-mode resonator, and the odd-even-mode method is adopted toanalyze its resonance characteristics, from which, its design graph is given. For the firsttime, a tri-band filter with three passbands whose center frequencies are controllable isimplemented by using only one dual-mode resonator. In bandpass filter design, the firstspurious occurring at4.2f0can be achieved by choosing a reasonable impedance and length ratio. In dual-and tri-band filter design, according to the voltage distributionalong the resonator, three passband external couplings can be controlled, and goodimpedance matching for each passband can be obtained.4. Based on stub-loaded resonators, serval kinds of tri-and quad-mode resonatorsare proposed, and systemically study on their resonance and coupling characteristics iscarried out. The proposed resonators can be used to design bandpass and dual-band filter.A dual-band filter designed by a novel short-circuit stub-loaded quad-mode resonatorfeatures compact size and wide stop-band property. Another dual-band filter based on anovel short-circuit stub-loaded square-loop resonator can exhibit high passbandselectivity and band-to-band isolation. Moreover, novel tri-and quad-mode resonatorsare proposed and employed to design bandpass filters.5. Systemically study on the characteristics of dual-frequency impedancetransformer, which is applied on the transformation of the two inequality impedance tothe standard one. Steeped-impdance resonator (SIR) can be regarded as generalizeddual-mode resonator, and its resonance characteristics are analyzed by theodd-even-mode method. Meanwhile, SIR feeded by stepped-impedance dual-frequencytransformer is functioned as common cavity, which is employed to design diplexers andquadruplexer. During the design, parameters extraction of the simulation model isutilized in the caculating of SIR resonant impedances at two frequencies. In this way,the dual-frequency impedance transformer can be designed more accurate andpractically.更多还原