模式匹配法及其在微波窗中的应用研究

发布时间：2018-09-12 19:49

【摘要】：模式匹配法(MMM)是建立在广义传输线理论之上、基于场理论的全波分析方法。目前,模式匹配法已经发展到了严格的场解析阶段,具有计算速度快、求解精度高和消耗计算机内存小的优点,成功应用于滤波器、耦合器、阻抗转换器、模式转换器、天线、多工器、功率分配器、反馈网络、移相器、偏光器、补偿弯波导、本征值问题以及手征介质的特性分析中。微波窗作为输入输出系统的重要组成部分,也是高功率微波系统的一个重要无源器件,它除了真空密封作用外,还具有馈送能量、透射微波、降低反射等作用,其质量好坏直接影响微波器件的电参数及其寿命。本文对模式匹配法及其在微波窗的应用进行了深入研究。对模式匹配法进行了详细的理论分析和解析推导,重点对S参数计算、相对收敛性、复功率守恒与电磁场匹配进行了理论分析与数值验证。应用模式匹配法对微波管中常见的四类窗结构(膜片加载矩形波导窗、多层介质圆波导窗、同轴窗和高功率盒型窗)进行了仿真设计,在高精度的前提下大大缩短了窗的设计周期。本论文的主要工作内容和创新点如下:1、系统深入地研究了模式匹配法,利用电磁场边界条件,建立了5种突变结(矩形-矩形、圆-圆、同轴-同轴、大矩-小圆、大圆-小矩)的广义散射矩阵。利用格林公式、离散傅里叶变换、坐标系转换以及归一化正交性等原理,推导出了这5类突变结上的模式之间的耦合矩阵解析解。2、利用矩阵级联理论以及传输线理论,推导出规则无源器件模型的广义散射矩阵的解析计算公式。基于MATLAB语言编写了模式匹配法程序包MMMS,并对模式匹配法的相对收敛性进行了研究。3、在模式匹配法的框架下,推导了各个模式在无源器件内传输的功率幅度系数,得到了无源器件在频带内任意截面的复功率,以及整个三维空间任意频点的电磁场分布。验证了电磁波传播过程中的复功率守恒与电磁场匹配。4、应用模式匹配法对4类常见微波窗进行了仿真设计,计算结果与三维电磁场数值模拟软件HFSS、CST、MTSS得到的模拟结果非常吻合,验证了模式匹配法相关理论推导与程序代码的正确性与可靠性。
[Abstract]:Mode matching method (MMM) is a full wave analysis method based on field theory and based on generalized transmission line theory. At present, the mode matching method has been developed to a strict field analysis stage, with the advantages of fast calculation speed, high accuracy and low memory consumption. It has been successfully applied to filters, couplers, impedance converters, mode converters, antennas, etc. In the analysis of multiplexer, power divider, feedback network, phase shifter, polarizer, compensated curved waveguide, eigenvalue problem and chiral medium. As an important part of input and output system, microwave window is also an important passive device in high power microwave system. In addition to vacuum sealing, microwave window also has the functions of feeding energy, transmitting microwave, reducing reflection and so on. Its quality directly affects the electrical parameters and lifetime of microwave devices. In this paper, the pattern matching method and its application in microwave window are studied. The theoretical analysis and analytical derivation of the pattern matching method are carried out in detail, and the theoretical analysis and numerical verification of S parameter calculation, relative convergence, complex power conservation and electromagnetic field matching are carried out. Four kinds of window structures (diaphragm loaded rectangular waveguide window, multilayer dielectric circular waveguide window, coaxial window and high power box window) are simulated and designed by mode matching method. On the premise of high precision, the design cycle of window is shortened greatly. The main contents and innovations of this thesis are as follows: 1. The pattern matching method is studied systematically and five abrupt junctions (rectangular rectangle, circular circle, coaxial, large moment and small circle) are established by using the boundary condition of electromagnetic field. The generalized scattering matrix of large circle and small moment. Based on Green's formula, discrete Fourier transform, coordinate system transformation and normalized orthogonality, the analytical solution of coupling matrix between the modes on these five kinds of abrupt junctions is derived, and the matrix cascade theory and transmission line theory are used. An analytical formula for the generalized scattering matrix of a regular passive device model is derived. Based on MATLAB language, the program package of pattern matching method (MMMS,) is written and the relative convergence of pattern matching method is studied. In the framework of pattern matching method, the power amplitude coefficients of each mode in passive devices are deduced. The complex power of passive devices with arbitrary cross section in the frequency band and the electromagnetic field distribution at any frequency point in the whole three-dimensional space are obtained. It is verified that the conservation of complex power and the matching of electromagnetic field during electromagnetic wave propagation. The simulation design of four kinds of common microwave windows is carried out by using the mode matching method. The calculated results are in good agreement with the simulation results obtained by the three-dimensional electromagnetic field numerical simulation software HFSS,CST,MTSS. The correctness and reliability of the related theoretical derivation and program code of the pattern matching method are verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN103

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