【作者】 廖平；

【导师】 杨中海；

【作者基本信息】 电子科技大学 ， 物理电子学， 2004， 博士

【摘要】 行波管是一种高增益的宽带微波/毫米波功率放大器件,广泛用于数据通信、电子对抗、预警飞机、火控雷达、精密制导,在现代军事电子装备中显示出不可取代的重要作用。行波管的研制涉及到电子光学、磁学、阴极电子学、微波电子学、电磁场理论、材料学、机械与热分析诸多学科,工艺过程十分复杂。计算机技术的发展与应用,极大地促进了行波管技术的进步。同时,提高行波管的设计能力,缩短开发周期,减少整管硬件实验,改善行波管性能,固化已有经验,也愈来愈离不开电子计算机,CAD 已经成为行波管研制的主要手段。本学位论文工作在总装备部军事电子预研“九五”重点项目“宽带大功率行波管 CAD 软件包研究”和总装备部军事电子预研“十五”重点项目“微波管 CAD设计技术研究”的资助下,对行波管电子光学系统进行了全面和深入的研究。将粒子模拟方法引入到电子光学系统的分析研究中,使用全三维电磁软件 MAFIA建立了行波管电子光学全系统的三维静电 PIC 模型。按照软件工程方法学方法,结合面向对象技术的最新发展以及行波管电子光学基本物理模型,开发了行波管电子光学系统 CAD 软件并集成进“宽带大功率行波管 CAD 软件包”中,为电子光学系统的设计和优化奠定了基础。本论文的主要工作和创新之处在于:1、研究了强流电子光学问题的基本方程组和数值求解方法。对旋转轴对称系统轴坐标系下的静电场、静磁场物理模型和物理方程,考虑空间电荷效应和相对论效应的电子运动方程和轨迹方程进行了深入分析。讨论了静态场的有限元和有限差分数值分析方法以及电子运动方程、轨迹方程、空间电荷密度的数学模型和数值解法。采用直接的矢量表示推导相对论电子运动方程比 EGUN 中通过线性方程组求解的方法更简化明了,二者在结果上是一致的。这些内容为行波管电子光学系统和 CAD 软件的研制奠定了理论基础。2、从电子光学系统的观点出发系统深入分析了行波管电子枪、周期永磁聚焦系统和多级降压收集极。研究了在空间电荷效应及发射电子热初速影响下发射电流在极间的流通规律,采用同时考虑空间电荷效应和热初速效应的 Langmuir 二极管模型对 3/2 次方定律进行了修正。分析了阴极电子初始热速度对电子注成形和电子注质量的影响以及栅控电子枪的设计问题。对于周期永磁聚焦系统研究了其结构和场分布以及小波动条件下电子注在 PPM 中的波动规律。对于收集极研究了多级降压收集极工作原理,收集极效率,二次电子对收集极的影响以及抑制二次电子发射的方法。为电子光学系统的 PIC 模拟分析打下了基础。 I<WP=10>中文摘要3、论文深入分析了以 EGUN 为代表的传统电子轨迹程序模拟电子光学系统的模拟方法和设计实现思想,指出了该方法存在的不足和缺陷。将粒子模拟方法引入到电子光学系统的分析研究中,建立了包括行波管电子枪、周期永磁聚焦系统和多级降压收集极在内的全系统 3-D 静电 PIC 模型,实现了电子从发射、成形、聚焦(传输)到收集全过程的模拟计算。4、电子枪模拟的关键在于如何以适当的方法从阴极发射电子,论文采用阴极等效温度和离散化发射角和能量级建立了阴极热电子发射模型,实现了电子枪的精确模拟。大量模拟计算表明该方法较其他电子轨迹程序相比,能够更准确地确定电子注的外形尺寸,包括电子注出口参数(射程和注腰),从而为磁聚焦系统的设计和模拟提供精确的初始条件。5、论文模拟了周期永磁聚焦系统中的场分布特性和电子注静态传输特性,讨论了磁场强度、磁场端部效应、横向速度分布和“过渡区”匹配对电子注聚焦性能的影响,为 PPM 聚焦系统的工程设计和优化提供了有价值的模拟结果。6、多级降压收集极效率是制约整管效率提高的重要因素,引起了各制管单位的高度重视。论文分析了传统二维轨迹程序在模拟非轴对称收集极、电子注入条件和模拟精度方面存在局限,提出了 MAFIA+大信号分析软件对多级降压收集极进行全三维动态 PIC 模拟的方法和收集极效率简化计算公式,模拟实例表明该方法与实验结果吻合较好,为我们深入分析收集极物理机理,研究影响收集极效率提高的制约因素以及改进和优化收集极设计提供了新的途径。7、论文提出了建立包括电子枪、周期永磁聚焦系统在内的一体化电子光学模型,使用 PIC 模拟研究电子注在整管中的静态传输性能的方法。该方法可以减少模拟中的假设和近似,有效缩短模拟时间,提高模拟精度,为实现行波管电子光学系统“一次设计制管成功”提供了新的方法。8、论文系统地运用面向对象建模技术、科学计算可视化方法和软件工程学思想开发了行波管电子光学系统 CAD 软件,可实现从电子枪、周期永磁聚焦系统到多级降压收集极的全面模拟和设计。系统总计 18 000 行 Visual C+ +源代码,运行于 Windows 操作系统,支持普通微机和工作站。具有人机界面友好,计算精度高,操作使用简单,计算过程实时动态显示和结果可视化的特点。9、论文根据有限元系数矩阵特征采用等带宽数据压缩存取技术实现了有限元数据的高效压缩和快速存取。结合电子枪计算域结构特点和有限元网格划分原则开发了四边形有更多还原

【Abstract】 Traveling wave tube is a kind of broad-band, high power, high gain microwavemillimeter wave amplifiers. They are widely used in communications, electronicwarfare, radar systems and microwave directional power weapon, taking anirreplaceable role in modern military electronic equipments. However, the manufactureprocess of TWT is so complicated that many kinds of subjects, such as electron optics,magnetics, cathode electronics, microwave electronics, electromagnetic fields theory,material science, mechanics and calorifics are involved in. With developments andapplications of computers, the technologies on TWT have been greatly improved so thatthe design abilities are enhanced, production period is reduced, hardware experimentsare decreased, the performance is improved and the have-known experiences aresolidified. Now CAD technology has become a main tool in TWT’s research andmanufacture. Supported by the “95 Plan” pre-study project of Wide Band High Power TWT CADSoftware Package Research and MWT CAD Design Technique Research of GeneralEquipment Ministry, this paper has studied comprehensively the TWT’ s electron opticssystem. By PIC method to analyze electron optics system, 3D electrostatic PIC model ofthe whole electron optics system has been established. Based on visualization techniqueof scientific calculation, object-oriented modeling technique and thoughts of softwareengineering, the TWT’ s electron optics system CAD software is developed andintegrated in Wide Band High Power TWT CAD Software Package for factorypracticality application and operation. The main work and innovations of this paper are listed as follows: 1、The basic equations of high density electron beam optics, as well as thenumerical analysis methods are studied and built in the dissertation. Especially thephysical models and physical equations in the electrostatic field and magnetostatic fieldin the axial symmetrical system are analyzed fully and deeply, with relativity correctionand space charge effect taken into account in the electron motion equations and theelectron trajectory equations. The finite element method (FEM) and finite differentialmethod (FDM) of the static field, the motion equations, and the space charge density arealso discussed. The vector presentation derived from electron motion equations is IV<WP=13>电子科技大学博士学位论文simpler than that of linear equation solution method used in SLAC. However, theoutcome of the two methods is almost the same. 2、The electron gun, the periodic permanent magnet(PPM) focusing system and themulti-stage depressed collector(MSDC) of TWT are fully analyzed according to theviewpoint of electron optics. The circulating law of emission current between electrodeswith the effect of space charge and initial thermal velocity are researched, and the 3/2square laws has been modified according to the Langmuir diode model in which thespace charge effect and the thermal initial velocity of electron at the cathode areconsidered. At the same time, the influence of the cathode initial thermal velocity on theformation and quality of electron beam is studied, and the design of the grid-controlelectron gun was researched. For PPM, the magnetic field distribution and the ripplerule of electron beam in periodic focusing magnetic field is studied. For collector, theworking principle of multi-stage depressed collector, the efficiency, the secondaryelectron emission and the way for restraining the secondary electron are also researchedin this dissertation. 3、The shortages of the traditional electron optical codes such as the known EGUNprogram for electron trajectory simulation are analyzed deeply. Particle-in-cell (PIC)simulation is introduced to the research of electron optics system. 3-D electrostatic PICmodel of electron gun, PPM and MSDC are set up, so the whole simulation processincluding the emission, forming, focusing (transmission) and collecting is更多还原