摘要近些年，无线通信飞速发展，射频/微波电路也日趋重要。微带双模滤波器是微波器件，由于它每个谐振器都能作为双调谐谐振电路使谐振器数减半，故能满足微波滤波器小型化特征，同时也能减少插入损耗。另外，双模滤波器的工艺较简单，应用广泛。64462

本文先论述了课题的意义和国内外研究现状，然后概述了滤波器的基础知识和微带线特性。基于仿真软件HFSS，介绍并仿真了两个小型化的微带双模滤波器，它们是带缺口的方形滤波器和带贴片的方环形滤波器。最后，本文基于方环形滤波器结构进行改进，从而设计出一种带电容性贴片的微带双模滤波器。针对这些滤波器，通过分析简并模和微扰结构来获得所需滤波器的尺寸,并利用HFSS进行优化，最终得到了较好的仿真结果。

毕业论文关键词  微波滤波器  双模滤波器  小型化  HFSS

毕业设计说明书（论文）外文摘要

Title    The Design of a Miniaturized Microstrip  Dual-mode Filter                                 

Abstract In recent years, the wireless communication develops rapidly and RF/ microwave circuits are becoming increasingly important. The microstrip dual-mode filter is a microwave device. Since each resonator of the microstrip dual-mode filter can be a double-tuned resonant circuit, the number of resonators can be halved. Therefore，it is able to meet the miniaturization of microwave filters and can also reduce the insertion loss of the filter appropriately. Besides, the crafts of the dual-mode filter are relatively easy and the filters can be applied in many fields.

This paper firstly discusses the significance of this topic and the research status at home and abroad. Then the basis knowledge on the filter and the microstrip is introduced. Based on the simulation software HFSS, two small microstrip dual-mode filters are designed and simulated. These filters consist of a square microstrip dual-mode filter with the notch perturbation and a square ring microstrip dual-mode filter with the patch perturbation. Finally, by improving the structure of the square ring filter, a microstrip dual-mode filter that contains some capacitive patches is proposed in this paper. By analyzing the degenerate modes and the perturbation structure, the size of the desired filters can be obtained. Moreover, I use the software HFSS to optimize these filters, and eventually get good simulation results.

Keywords  Microwave filter  Dual-mode filter  Miniaturization  HFSS

 1  绪论  1

1.1  课题意义  1

1.2  微波双模滤波器的国内外研究现状  1

2  滤波器的基本理论和设计  3

2.1  滤波器概述和工作原理  3

2.2  滤波器的散射参量  5

2.3  低通原型滤波器  8

2.4  微带线谐振器  10

2.5  微带线滤波器  13

2.6  微带滤波器的设计  15

2.7  微带双模滤波器的设计  18

3  带缺口微扰的方形微带双模滤波器  19

3.1  简并模分析  19

3.2  微扰结构  23

3.3  馈电方式  23

3.4  优化  23

4  带贴片微扰的方环形微带双模滤波器  24

4.1  简并模分析  24

4.2  微扰结构  26

4.3  优化  27

5  改进的方环形微带双模滤波器  28

5.1  简并模分析  28

5.2  微扰结构  29

5.3  优化  30

结论  32

致谢  33