微波管永磁聚焦系统三维有限元理论及CAD技术研究

发布时间：2018-05-14 04:01

本文选题：微波管 + 永磁聚焦系统　；参考：《电子科技大学》2016年博士论文

【摘要】：作为一类重要的微波/毫米波电真空器件,微波管在卫星通信、雷达、电子对抗等领域具有不可替代的作用。永磁聚焦系统是微波管中使用频率最高的一种聚焦系统,也是微波管电子光学系统的组成部分之一。它主要被用于维持电子注形状,保证电子注的稳定传输。其设计的优劣对微波管的性能有直接影响。微波管磁系统的设计以往是通过一定假设条件下经过简化而得到的近似式,它只能是给出磁系统结构、磁体形状尺寸的一种简便估算方法,更精确的设计还是需要通过计算机模拟来实现。此外,一些新型永磁聚焦结构如Wiggler,PMQ,PCM等,都具有非对称的特性,必须进行全三维的磁场仿真模拟,以便设计、验证和优化磁聚焦结构。因此,永磁系统的CAD软件是微波管设计工作必备的基础工具之一,它为永磁系统的设计提供强有力的保障。本论文就是在这样的背景下立题的,在深入研究微波管永磁聚焦系统的有限元理论基础上,开发了微波管永磁聚焦系统磁场分析软件,本文主要工作及创新点如下:1、对微波管永磁聚焦系统的磁矢势和磁标势有限元理论进行研究。首先从麦克斯韦方程组出发,建立了永磁聚焦系统磁场求解的磁矢势有限元理论和磁标势有限元理论。通过一个单磁环的仿真,表明在三维的有限元仿真中磁标势有限元方法计算效率高于磁矢势有限元方法。2、对非线性材料的磁场计算方法进行研究,提出了处理非线性极靴材料牛顿迭代+抛物线算法。通过一个四周期永磁聚焦系统的仿真,分析了这几种非线性材料的模拟计算方法的收敛性和计算效率,结果表明牛顿迭代+抛物线算法的效果最好。同时,本文还提出了专门处理非线性永磁材料的迭代算法,通过一个单磁环实例验证了算法的收敛特性。3、对开域磁场问题的边界处理技术进行研究。从磁矢势和磁标势有限元理论出发,建立了轴对称永磁结构和非轴对称永磁结构的渐近边界条件。对于轴对称结构,通过单磁环和三周期永磁结构的模拟,结果表明随真空大小变化渐进边界计算结果收敛会快于要截断边界。对于非轴对称永磁结构,通过三周期永磁结构,带开口磁环的三周期永磁结构和Wiggler结构的模拟,结果表明随真空大小变化渐近边界技术会略优于诺曼边界技术和截断边界技术。4、基于永磁系统某些结构的对称性,在三维永磁系统模拟器中采用了局部对称的计算方法,在不损失计算精度的前提下,通过对称性减小计算区域来提高计算效率,减少计算资源消耗。5、对网格自适应的后验误差估计和网格加密策略进行研究,设计了一个能够有效控制网格加密数的加密策略。通过PPM和Wiggler结构分析了本文网格自适应方法的收敛特性。同时,本文还把网格自适应技术应用到电子光学和高频电路的有限元模拟。另外,本文针对电子枪和螺旋线高频结构提出了专门的网格加密处理技术。6、在上述微波管永磁系统有限元理论及关键技术基础上,开发了具有完全自主知识产权的三维微波管永磁系统磁场仿真设计软件——永磁系统磁场模拟器(MFS)。MFS包含二维和三维的磁场计算程序,支持对永磁系统涉及的结构参数和材料参数进行优化,能够方便的把永磁系统计算结果导入本实验室开发的电子光学模拟器(EOS)和注波互作用模拟器(BWIS)进行电子束传输及注波互作用模拟。
[Abstract]:As an important class of microwave / millimeter wave electrical vacuum devices, microwave tubes have an irreplaceable role in the fields of satellite communication, radar and electronic countermeasures. The permanent magnetic focusing system is one of the most frequently used focusing systems in microwave tubes, and is also one of the components of the electronic optical system of the microwave tube. It is mainly used to maintain the electron beam shape. The design has a direct effect on the performance of the microwave tube. The design of the microwave tube magnetic system is the approximate formula obtained by simplification under certain assumptions. It can only be a simple method of estimating the structure of the magnetic system and the shape size of the magnet. More accurate design or need is needed. In addition, some new permanent magnetic focusing structures, such as Wiggler, PMQ, PCM and so on, have asymmetric characteristics. All three dimensional simulation of magnetic field must be carried out in order to design, verify and optimize the magnetic focusing structure. Therefore, the CAD software of the permanent magnet system is one of the basic tools for the design of the microwave tube. The design of the magnetic system provides a strong guarantee. This paper is based on this background. On the basis of the deep study of the finite element theory of the microwave tube permanent magnetic focusing system, the software of the magnetic field analysis of the permanent magnetic focusing system of the microwave tube is developed. The main work and innovation are as follows: 1, the magnetic vector potential and the magnetic vector potential of the permanent magnetic focusing system of the microwave tube The magnetic potential finite element theory is studied. First, starting from the Maxwell equation group, the magnetic vector potential finite element theory and the magnetic potential finite element theory for the magnetic field solution of the permanent magnetic focusing system are established. The simulation of a single magnetic ring shows that the calculation efficiency of the magnetic potential finite element method in the three-dimensional finite element simulation is higher than the magnetic vector potential finite element method. Method.2, the method of magnetic field calculation for nonlinear material is studied, and the Newton iteration + parabola algorithm for nonlinear pole material is proposed. Through a simulation of a four period permanent magnetic focusing system, the convergence and calculation efficiency of the simulation calculation methods of these nonlinear materials are analyzed. The results show that the Newton iteration + parabola algorithm is used. At the same time, an iterative algorithm for dealing with nonlinear permanent magnets is also proposed. Through an example of a single magnetic loop, the convergence property of the algorithm.3 is verified. The boundary treatment technology for the open domain magnetic field problem is studied. From the magnetic vector potential and the magnetic potential finite element theory, the axisymmetric permanent magnetic structure and non axisymmetric permanent magnet are established. The asymptotic boundary condition of the structure. For the axisymmetric structure, the simulation of the single magnetic ring and three periodic permanent magnetic structure shows that the convergence of the asymptotic boundary calculation with the change of the vacuum is faster than the truncated boundary. For the non axisymmetric permanent magnetic structure, the three periodic permanent magnetic structure and the Wiggler junction with the open magnetic ring are carried out through the three periodic permanent magnetic structure. The simulation results show that the asymptotic boundary technology with the change of vacuum size is slightly better than the Norman boundary technique and the truncated boundary technique.4. Based on the symmetry of some structures of the permanent magnet system, the local symmetry calculation method is adopted in the three-dimensional permanent magnet system simulator, and the calculation area is reduced by symmetry without loss calculation precision. In order to improve the computational efficiency and reduce the consumption of computing resource.5, the adaptive posterior error estimation and the grid encryption strategy are studied, and an encryption strategy that can effectively control the number of grid encryption is designed. The convergence characteristics of the grid adaptive square method are analyzed by PPM and Wiggler structure. The technology is applied to the finite element simulation of electronic optics and high frequency circuits. In addition, a special grid encryption technology.6 is proposed for the high frequency structure of the electron gun and the spiral line. On the basis of the finite element theory and key technology of the above microwave tube permanent magnet system, a three dimensional microwave tube permanent magnet system with complete independent intellectual property rights is developed. The permanent magnetic field simulator (MFS).MFS contains two and three dimensional magnetic field calculation program, which supports the optimization of the structure parameters and material parameters involved in the permanent magnet system, and can easily import the results of the permanent magnetic system into the open electronic optical simulator (EOS) and the injection wave interaction mode in our laboratory. Simulator (BWIS) is used to simulate electron beam propagation and beam wave interaction.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN12

【参考文献】