"电磁场与电磁波"课程可视化方法研究

本文将"电磁场与电磁波"课程中的可视化问题进行了分类,指出了每类问题可视化的方法、应用软件与注意事项.电磁场是矢量场,矢量线(电力线和磁力线)图清晰、美观,不仅能反映电磁场的全局概况和场与源的关系,还能全面描述电磁场的性质,但是难以绘制,本文根据实例详述了用Matlab绘制矢量线图的方法和技巧.     

一种新的电磁场数据三维绘制算法

针对波束方程采样得到的电磁场数据,提出了一种新的三维绘制算法。算法首先利用波束方程按角度值对电磁场表面采样得到点云数据,然后通过对点云数据进行归一化处理、极坐标转换为三维立体坐标、为点云数据的属性值映射包含颜色和透明度的特征值的可视化映射方法,以及利用三角形带进行波束表面绘制等过程将电磁场数据显示出来。实现的算法已经用于武器装备的电磁兼容综合测试与分析系统,取得了很好的可视化效果,绘制效率高,并在最后给出了实验结果。     

场线绘制方法的讨论

在电磁场课程中,绘制场线具有比较重要的理论和实际意义,同时还是进行研究型教学的良好载体.本文以电场线为例讨论了绘制电磁场场线的3种方法:自适应步长法、自适应方向法和切线方向法,并介绍了这3种方法的基本思想,定性和定量对其进行了比较.     

基于Matlab的点电荷镜像法电场的可视化

点电荷的镜像法是“电磁场与电磁波”课程的重要内容。这部分的教学重点通常在于分析镜像法原理和寻找镜像电荷,但是缺乏对镜像电场空间分布的图形描绘。本文用Matlab软件对镜像电场进行仿真,绘制了点电荷镜像法中多种镜像电场的等位面和电力线细节图,对镜像电场进行了可视化。可视化有利于加深学生对镜像法原理、镜像电荷和镜像电场分布的理解。     

MATLAB在"电磁场"教学中的应用

针对电磁场教学的难点,通过形象化的场图等辅助手段帮助学生理解和掌握电磁场的规律。介绍了科学计算语言MATLAB的特点及其在辅助教学中的应用,详述了MATLAB在电磁场教学中的一些具体应用实例,包括利用可视化功能进行场图绘制、三维图形交互,运用符号运算功能进行数学公式推导,根据数值计算功能进行习题求解等。最后还介绍了利用MATLAB的PDE工具箱给学生有限元法的初步认识。     

叠加法巧析对称场

静态对称场是“电磁场与电磁波”课程中的基本模型,叠加法是“电磁场与电磁波”课程中解决问题的重要方法,它可以化抽象为具体,增强直观性。论文将应用叠加原理来分析电磁场中常见的对称场,通过对场进行巧妙的叠加与抵消,进一步论证静电场以及恒定磁场的对称性,有利于强化人们对场对称性分布的理解。     

叠加法巧析对称场

静态对称场是“电磁场与电磁波”课程中的基本模型,叠加法是“电磁场与电磁波”课程中解决问题的重要方法,它可以化抽象为具体,增强直观性。应用叠加原理来分析电磁场中常见的对称场,通过对场进行巧妙地叠加与抵消,进一步论证静电场以及恒定磁场的对称性,有利于强化人们对场对称性分布的理解。     

利用MATLAB进行电磁学计算及可视化教学

电磁场与电磁波是一门难度较大的课程,其较深的数学理论和场的抽象性使得学生在学习中往往有恐惧心理,很难产生学习兴趣。本文通过几个典型例子介绍利用MATLAB软件工具进行电磁场电磁波的辅助教学,显示了MATLAB在电磁学的计算及可视化方面的优越性,可以较好地改善教学效果。     

基于可视化案例的电磁场课程教学改革与实践 ——以散度定理为例

电磁场课程是电气信息类专业本科生的一门专业基础课。该文分析了电磁场课程的教学特点,提出了基于MATLAB软件的电磁场课程可视化案例教学方法,将矢量分析与场论的重点内容经过整理,提炼成实验项目,形成可视化的图像资料,配合理论教学。实践证明,通过可视化案例教学的改革实践,不仅使学生加深了对抽象电磁场理论的理解,同时提高了学生利用MATLAB软件解决问题的实践能力。     

MATLAB在反射面天线三维方向图中的应用

提出了一种反射面天线三维方向图的绘制方法。介绍了分析反射面天线辐射场的方法,并将表面电流法和口径场法进行了比较。给出了计算抛物面上的电流分布公式,论述了表面电流法的基本原理。运用MATLAB软件对反射面天线的辐射场进行了数值计算,阐述了程序主要语句格式和功能以及计算的流程图,得到了天线的二维和三维方向图,直观清楚地表现出辐射方向图的特点,为绘制反射面天线的方向图提供了一种方法。     

Transient Analysis of a Stripline Having a Corner in Three-Dimensional Space

The transient analysis of electromagnetic fields has shown its utility not only in clarifying the variation of the fields in time but also in gaining information on mechanisms by which the distributions of an electromagnetic field at the stationary state are bronght about. We have recently proposed a new numerical method for the transient analysis in three-dimensioual space by formulating the equivalent circuit based on Maxwell's equation by Bergeron's method. The resultant nodal equatiou is uniquely formulated in the equivalent circuit for both the electric field and the magnetic field. In this paper, we deal with the stripline which should be analyzed essentially in three-dimensionaf space because of its structure, The time variation of the electric and magnetic field of the stripline having a comer is analyzed and the remarkable changing of distribution of the field is presented as a parameter of time and of conditions imposed by the corner stucture.     

On the electromagnetic field of a rectangular patch of uniform andlinear distributions of current in the source region

Exact analytical expressions for the magnetic vector potential and the electric and magnetic fields of a rectangular patch of uniform and linear distributions of electric current in an unbounded homogeneous medium have been given by the authors in a previous paper (see ibid., vol.37, p.1503-9, December 1989). In this paper, these expressions are utilized to investigate the nature of the electromagnetic field of such current distributions in the source region. Specifically, the singular parts and points of singularity of the various functions involved in the analytical expressions, as well as those of the field components of both current distributions, are obtained and tabulated     

Experimental study of the field structure of the surface electromagnetic wave in an anisotropically conducting tape

It is shown that, in the frequency band 3–5.2 GHz, a tape of metal conductors supports slow waves. The field structure of the surface wave in an anisotropically conducting tape is studied experimentally. It is found that the electromagnetic field of the tape has three electric and two magnetic components. Intensity distributions of all field components, the slowing factor of the surface wave, and the loss per unit length are measured.     

Modelling of through silicon via and devices electromagnetic coupling

This paper is essentially composed of two parts for future synthesis. We developed 2D and 3D simulations, starting from a 0.35 μm standard CMOS technology, focusing on through silicon via or redistribution layer induced coupling; nMOSFET, pMOSFET, and the sensitive regions of the CMOS inverter are investigated. We also study stacked devices in 3D circuits, in the radiofrequency range, and propagation of electromagnetic waves along some interconnections with discontinuities. This study is performed in the time domain—a finite-difference time-domain method is applied to the analysis of some vias flanked by two striplines, all embedded in silicon. Electric and magnetic field distributions, transmission and reflexion parameters, and pulse propagations along a transverse via are presented.     

表面波放电狭缝天线辐射电磁场的三维数值分析

针对平板型表面波放电等离子体源,建立了表面波放电狭缝天线辐射电磁波模型,对狭缝天线辐射电磁场分布进行了三维数值计算,并与表面波电磁场进行对比分析,讨论了平板型表面波放电机理。结果表明:整个狭缝天线阵激发的电磁场是每个狭缝天线激发电磁场的线性叠加;狭缝天线阵直接激发的电磁场强度在临近波导壁面处很大,并且随着空间距离的增大迅速衰减;狭缝天线阵直接激发和表面波的电场均远大于各自的磁场,分析电、磁场对带电粒子的力作用时可以忽略磁场力的作用;表面波电磁场远大于狭缝天线阵直接辐射的电磁场,强电磁场范围也远大于狭缝天线阵直接激发的强电磁场范围,等离子体有增强电磁场强度、扩大强电磁场范围的作用。     

On the modal expansion of resonator field in the source region

Two field expansions for the electromagnetic field radiated by electric and magnetic currents in a cavity resonator are presented. The first utilizes the cavity resonant modes only, while the other utilizes, in addition, the irrotational modes. The first expansion is shown to be more suitable if the exciting currents have volume distributions. On the other hand, the second expansion is more suitable if the resonator contains surface or filamentary current distributions. Typical examples are given to demonstrate the convergence behavior of the two expansions near and within the source region     

矩形波导TE10模的仿真与分析

针对矩形波导TE10模的特点,为了提高电磁设计性能,设计出矩形波导TE10模的仿真模型。本文首先根据电磁场传播理论,采用直角坐标系分析对无源自由空间电场和磁场采用矢量亥姆霍茨方程分析,得出矩形波导中传输模式及其场分布,然后分析了矩形波导中传输模式的纵向传输特性,最后利用HFSS软件对矩形波导TE10模的场结构进行三维空...     

Theoretical and experimental characterization of theEMP-interaction with composite-metallic enclosures

A numerical procedure is developed for the prediction of the electric and magnetic field distribution inside an enclosure having aluminum and carbon-fiber reinforced composite (CFRC) walls, illuminated by a transient electromagnetic plane wave. The composite panel is simulated by an effective layer model; time-domain surface impedance boundary conditions are enforced on the external faces of the composite slab, to express the relations among the tangential electric and magnetic field components. A coupling model for the calculation of the current induced along thin wires inside the enclosure is presented. The proposed models are implemented in a three-dimensional (3-D) finite-difference time-domain (FDTD) procedure, which is applied to the analysis of the shielding performances of an aluminum box with one CFRC face, illuminated by a transient electromagnetic wave. The computed results are compared with measured data obtained by using a full scale EMP generator     

Adaptive finite element-boundary integral analysis for electromagnetic fields in 3-D

This paper presents a complete adaptive finite element-boundary integral (FE-BI) analysis scheme for the time-harmonic, electromagnetic analysis of three-dimensional inhomogeneous scatterers/radiators in free-space. The adaptive scheme is based on an FE-BI formulation which yields electric and magnetic field solutions simultaneously. It employs a posteriori error estimates which exploit the availability of both field solutions and estimates error distributions and global solution quality for the electric and magnetic fields separately. It automatically determines which elements should be refined in order to equi-distribute the estimated error, based on the type of refinement requested (h,p or hp). This automatic determination is based on extrapolating the elemental error estimates. The algorithm terminates when specified tolerance levels are reached by the electric and/or magnetic field global solution quality estimates. The only required user specifications within the algorithm are the termination tolerances and the types of refinements to effect. Results are presented which show that within the scope of the presented error measures significant reductions in computational cost may be achieved. The proposed scheme could be used with other types of error estimates and it could be adapted to other FE or FE-BI formulations.