毕业设计说明书中文摘要 最近的许多年来，通信系统和无线通信正在飞快发展，在商业和军事等方面都对接受和传输的信号的要求越来越高。

    作为微波、毫米波系统中非常重要的无源器件，环形电桥影响着系统的发展空间和优越性， 其性能的好坏会对整个系统的质量产生极大的影响。这篇论文的主要内容是从单频环形电桥的设计开始进行：81375

    首先，介绍了微带环形耦合器近年来的研究背景，同时介绍了定向耦合器和单频环形电桥，并总结了环形电桥的研究进展。

    其次，简单讲解了利用四分之波长阻抗变换器等效在传统耦合器中阻抗的方法，使用增加短截线来实现传统耦合器工作在双频的方法，介绍了基于Π型阻抗变换器的双频环形耦合器的频率比分析，并将其运用到双频环形电桥的设计中去。

    最后，仿真并加工了一个工作在频率5GHz 和7GHz 的双频环形电桥，建立在Π 型双频环形电桥上，端口回波损耗>15dB，隔离度>20dB，仿真结果与所需结果较吻合。 

毕业论文关键词： 耦合器 环形 双频 小型化

毕业设计说明书外文摘要

Title    Dual-band rat-race coupler design                     

Abstract In recent years, communication systems and wireless communications are developing rapidly, and the requirement for the acceptance and transmission of signals in both commercial and military fields is becoming more and more high。

As a very important passive component in microwave and millimeter wave system, the ring bridge affects the development space and the superiority of the system。 The performance of the ring bridge will have a great influence on the quality of the whole system。 The main content of this paper is from the design of the single frequency ring bridge:

Firstly, this paper introduces the research background of microstrip ring coupler in recent years, introduces the directional coupler and single frequency ring bridge, and summarizes the research progress of the ring bridge。

Secondly, a brief explanation of the quarter wavelength transformer equivalent in traditional coupler impedance method, the increased use of stubs to achieve traditional coupler in the dual frequency method, introduces the frequency of the n-shaped impedance converter dual ring coupler based on ratio analysis, and applied it to the design of dual band ring bridge。

Finally, simulation and processing a job in 5GHz and 7GHz frequency ring bridge, built on PI type dual band ring bridge, port return loss >15dB, isolation >20dB。 Simulation results and the need results are in good agreement。

Keywords: Coupler;Dual-band; rat-race;Miniaturization

目   次

1  引言 1

1。1  研究背景和意义 1

1。2 双频环形电桥研究现状 2

1。3 主要内容和工作安排    2

1。4 结论 3

2 定向耦合器基本理论 4

2。1 定向耦合器的基本结构 4

2。2 四端口定向耦合器的理论介绍 4

2。3 传统 3dB 定向耦合器的特性 6

3 单频环形电桥的介绍