万方数据
万方数据
摘 要
摘 要
随着通信技术的迅猛发展，通信频率资源越来越紧张，微波频段之间的间隔 越来越密，这就对微波滤波器的性能提出了更高的要求。低差损、高抑制、高功 率、时延平坦、小体积、低成本以及快速设计成为滤波器设计的关键技术要求。
本文研究了滤波器传输零点的特性，重点是对带传输零点的波导腔体滤波 器、双工器及其交叉耦合极性进行研究。波导滤波器作为滤波器类型的一种，具 有低差损、功率容量大 、容易批量生产的特点，并且工作频率可达毫米波波 段，通信系统中应用广泛。高性能波导滤波器及双工器也成为国内外微波无源器 件的研究热点。
本文主要内容概括如下：
1．研究了交叉耦合滤波器的基本理论。推导了切比雪夫和广义切比雪夫函 数多项式，给出了耦合矩阵综合过程，介绍了两种耦合系数计算方法及对耦合极 性与传零点关系进行了分析。
2．分析了一种在微带及同轴腔滤波器设计中简单的耦合极性改变方法，详 细讲述了 CT，CQ 拓扑结构波导交叉耦合滤波器。介绍了通过 TE102 模腔改变交叉 耦合极性方法以及提出一种基于模式匹配法软件μWave 的交叉耦合波导滤波器 的快速设计方法。并且仿真设计出几个交叉耦合滤波器验证理论。
3．详细分析了过模腔在带传输零点波导滤波器设计中的理论，其中包括简 并和非简并过模腔理论，仿真设计出带传输零点的过模腔滤波器。并且还提出了 一种新的改变耦合极性的方法。
4．设计了两款高性能的 H 面感性膜片波导双工器，构成双工器的滤波器均 是交叉耦合滤波器，产生传输零点。通过前面理论讲的耦合变性方法及设计方 法，很方便地设计出零点位于通带高端或低端的高性能滤波器。最后加工出双工 器实物进行了测试，很好的满足了指标要求。
关键词：交叉耦合，波导滤波器，双工器，传输零点，耦合极性
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ABSTRACT
ABSTRACT
With the dramatically rapid development of communications, the spectrum resource is increasingly lacking and the space separation between microwave bands is more and more small, thus posing more stringent requirements on the performance of microwave devices. Lower insertion loss, higher isolation, higher power handling, flatter group delay, more compact size and faster design, for instance, are the main key technological requirements.
The characteristics of TZs of microwave filters are investigated in this paper, and the waveguide filters and diplexers with TZs are studied intensively. Waveguide filters, as a class of microwave filters, carry many strengths, such as low insertion loss, high power handling and easy batch manufacture, etc. Moreover, they can work at millimeter
–wave bands, which have found extensive applications in communications systems. Waveguide filters and diplexers with high performance are also the hot research points in the microwave passive devices around the world.
The main results in this paper are summarized as follows:
Basic theory concerning cross-coupled filters are reviewed. Chebyshev and general Chebyshev polynomials are derived and the synthesis procedures of coupling matri}