带短路支节的高隔离度分支线定向耦合器设计研究

发布时间：2018-05-03 07:25

本文选题：定向耦合器 + 隔离度　；参考：《南京邮电大学》2015年硕士论文

【摘要】：定向耦合器是一种常用微波无源元件,在无线系统的射频前端中有着广泛的应用。特别在收发同频的无线系统中定向耦合器常常被用作隔离收发信号的一种关键部件。但是传统的定向耦合器隔离度偏低且工作带宽较窄,无法满足系统的要求。本文以分支线定向耦合器为研究对象,主要围绕如何提高其隔离度和增加工作带宽来进行深入研究。论文的主要工作和创新点包括:(1)根据功率相消原理在其耦合端口增加一条微带短路支节,设计出一款3dB带短路支节双分支线定向耦合器。这种方法结构简单,易于实现,且能够大幅提高耦合器隔离度。完成了一款实验样品的加工、测量工作,验证了短路支节线用于提高双分支线定向耦合器隔离度的效果,以及工作带宽提高不明显的缺点。(2)在双分支线定向耦合器基础上,总结出一种有效提高其工作带宽的方法:增加耦合路径,并设计出一款3dB三分支线定向耦合器,该耦合器能够大幅拓宽工作带宽。在3dB带短路支节双分支线定向耦合器的基础上设计出一款3dB带短路支节三分支线定向耦合器,该款改进型定向耦合器在很大程度上拓宽了工作带宽,且提高了隔离度。
[Abstract]:Directional coupler is a kind of microwave passive component, which is widely used in RF front end of wireless system. Especially in wireless systems, directional couplers are often used as a key component in the isolation of transceiver signals. However, the traditional directional coupler has low isolation and narrow bandwidth, so it can not meet the requirements of the system. This paper focuses on how to improve the isolation and bandwidth of branch line directional coupler. The main work and innovation of this paper include: (1) according to the principle of power cancellation, we add a microstrip short circuit branch to the coupling port and design a double branch line directional coupler with 3dB short circuit branch. This method is simple in structure, easy to implement and can greatly improve the isolation of coupler. The processing and measurement of an experimental sample have been completed. The results show that the short-circuit branch cable is used to improve the isolation degree of the directional coupler with double branch lines, and the shortcoming of improving the working bandwidth is not obvious. (2) on the basis of the double branch line directional coupler, the short circuit branch cable is used to improve the isolation degree of the directional coupler. In this paper, a method to increase the working bandwidth is summarized. The coupling path is increased, and a 3dB three-branch directional coupler is designed. The coupler can greatly widen the working bandwidth. A 3dB three-branch directional coupler with short circuit branch is designed on the basis of the dual-branch line directional coupler with short circuit branch of 3dB. The improved directional coupler widens the working bandwidth to a great extent and improves the isolation degree.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN622

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