毫米波行波管输入输出系统的设计研究

发布时间：2018-06-25 21:16

本文选题：毫米波行波管 + 同轴窗　；参考：《电子科技大学》2016年硕士论文

【摘要】：毫米波行波管在国防和国民经济领域发挥着越来越重要的作用,并不断向更高频率、更大功率以及更宽频带方向发展。输入输出系统是毫米波行波管的关键部件之一,其性能直接影响到行波管的带宽、功率容量等性能。本论文对毫米波行波管输入输出系统进行了理论和仿真设计研究,并针对32GHz~36GHz的毫米波螺旋线行波管的输入输出系统进行了设计与优化,分析了输入输出系统各部分对传输性能的影响,为毫米波行波管输入输出系统的设计和研制提供了参考。论文主要工作和创新点如下:1、提出了典型同轴窗的两种快速设计方法。一种设计方法是基于等效电路模型,根据同轴窗在中心频率处反射等于零计算同轴窗的初始尺寸,是针对整个窗结构的全局匹配。第二种设计方法是通过使窗片平面处的输入导纳与窗片的特性导纳相等来计算同轴窗的初始尺寸,是一种保证窗片内电磁波为行波的局部匹配。利用两种方法分别对同轴窗进行了设计,通过理论值与实验值的对比,证明了这两种设计方法的正确性,为以后同轴窗的快速设计提供参考。2、对比了两种台阶电容计算公式的正确性与适用性。同轴线半径不连续的地方表现在等效电路上可等效为一个台阶电容。本文对两种台阶电容的计算方法进行了比较。对同一个同轴阶梯,两者计算电容值相差很大。但是,当它们应用于同一个窗的设计时,所得到的设计结果(窗的尺寸和传输特性)却是几乎一致的。3、对传统?4阻抗匹配器进行了改进。本文慢波结构与输入输出窗的连接部分为二节?4阻抗匹配器。鉴于同轴窗内导体半径与螺旋线截面外接圆半径不同,为了减小不连续电抗,将阻抗匹配器的内导体结构优化为直线渐变型。经过对整管的仿真,本文阻抗匹配器结构的改进优化了整个输入输出系统的传输性能。4、分析了输入输出系统各关键参量对传输性能的影响。本文分别对螺旋线圈数、拉伸螺距值、夹持杆纵向延伸位置、阻抗匹配器外半径、连接金属体的结构、窗片尺寸、窗片上下空气柱高度等关键参量进行了扫描计算,得到了各参量大小与输入输出系统传输性能的关系。最后优化出了一只32GHz~36GHz的毫米波行波管输入输出系统,在整个工作频带内其驻波系数均小于1.42,传输性能良好。
[Abstract]:Millimeter wave traveling wave tube (MWTWT) is playing an increasingly important role in the field of national defense and national economy, and has been developing to higher frequency, higher power and wider frequency band. Input-output system is one of the key components of millimeter-wave TWT. Its performance directly affects the bandwidth and power capacity of TWT. In this paper, the theoretical and simulation design of the millimeter-wave traveling wave tube input and output system is studied, and the input and output system of the millimeter wave helix traveling wave tube at 32GHz is designed and optimized. The influence of the input and output system on the transmission performance is analyzed, which provides a reference for the design and development of the millimeter wave traveling wave tube input and output system. The main work and innovation are as follows: 1. Two fast design methods of typical coaxial window are proposed. One design method is based on the equivalent circuit model. The initial size of the coaxial window is calculated according to the reflection equal to zero at the center frequency of the coaxial window, which is a global matching for the whole window structure. The second design method is to calculate the initial size of the coaxial window by making the input admittance at the plane of the window plate equal to the characteristic admittance of the window plate. It is a local matching method to ensure that the electromagnetic wave in the window plate is a traveling wave. The two methods are used to design the coaxial window. The correctness of the two design methods is proved by comparing the theoretical value with the experimental value. It provides a reference for the fast design of coaxial window in the future, and compares the correctness and applicability of the two formulas for calculating step capacitance. Where the coaxial radius is not continuous, the equivalent circuit can be equivalent to a step capacitance. In this paper, two calculation methods of step capacitance are compared. For the same coaxial ladder, the calculated capacitance between the two is quite different. However, when they are applied to the design of the same window, the design results (the size and transmission characteristics of the window) are almost the same. In this paper, the connection between the slow wave structure and the input and output window is divided into two sections and four impedance matchers. In order to reduce the discontinuous reactance, the inner conductor structure of the impedance matcher is optimized as a linear gradient type in view of the difference between the radius of the conductor in the coaxial window and the radius of the outer circle of the helical section. Through the simulation of the whole transistor, the structure of the impedance matcher is improved to optimize the transmission performance of the whole input and output system. The influence of the key parameters of the input and output system on the transmission performance is analyzed. In this paper, the key parameters, such as the number of helix coils, the tensile pitch value, the longitudinal extension position of the clamping rod, the external radius of the impedance matcher, the structure of the connecting metal body, the size of the window piece, the height of the upper and lower air column of the window piece, etc. The relationship between the size of the parameters and the transmission performance of the input and output systems is obtained. Finally, a 32GHz / 36GHz millimeter-wave TWT input and output system is optimized. The standing wave coefficient is less than 1.42 in the whole operating frequency band, and the transmission performance is good.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN124

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