电磁脉冲参数对材料屏蔽效能影响研究

采用基于有限积分方法的电磁仿真软件CST-MWS建立电磁脉冲辐照条件下材料屏蔽效能测试模型,提出脉冲峰值屏蔽效能和脉冲能量屏蔽效能两个方案来评价材料屏蔽能力,并通过仿真分析了电磁脉冲上升时间和脉宽对屏蔽效能的影响。结果表明,脉冲上升时间相对于脉宽对屏蔽效能的影响较大,上升时间越短,屏蔽效能越高,峰值屏蔽效能高于能量屏蔽效能;脉宽对于材料的峰值屏蔽效能基本没有影响,能量屏蔽效能随着脉宽的增大而减小。     

通信电台电磁脉冲阻塞效应规律与作用机理

为揭示通信电台电磁脉冲阻塞效应机理,在受试电台正常工作状态下,借助注入耦合模块实验研究了阶跃脉冲串和双指数脉冲串对数字通信电台误码率的影响规律。引入电磁脉冲对受试设备影响时间的概念,建立了与连续波阻塞效应等价的电磁脉冲阻塞敏感判据。实验结果表明:电磁脉冲对受试设备的影响时间取决于脉冲波形,可通过效应试验测试确定。在电磁脉冲重复率较低时,受试电台的临界干扰电平与脉冲重复率无关,属于单脉冲效应;当脉冲重复率大于电磁脉冲影响时间的倒数时,受试电台的临界干扰电平随脉冲重复率增加而降低,属于多脉冲累加效应。将电磁脉冲在影响时间窗口内进行频谱分析,采用连续波带内多频阻塞效应模型进行验证,误差在2dB以内。     

An Experimental Investigation of the Distribution of Current And Charge Induced on a Tubular Conducting Cylinder by an Electromagnetic Pulse

The distribution of current and charge induced on a tubular cylinder by an electromagnetic pulse (EMP) is investigated experimentally in the Harvard parallel-plate EMP simulator (HES). The pulse shapes of the current and charge induced on the surface of the cylinder are measured. After Fourier transforms of the observed pulse shapes are taken, the distributions of the several frequency components on the surface are obtained. The measured distribution of each frequency component is then compared with the theoretical distribution calculated using Kao's method.     

电磁脉冲斜入射时无限长近地细导线表面电流的计算

本文应用时域有限差分（FDTD）方法研究电磁脉冲斜入射下无限长细导线的表面感应电流,并考虑了有耗地面的影响,该问题可以转换为二维问题来计算,从而大大节约计算资源,文中给出了各种情况下的感应电流计算结果。     

Plane wave coupling to multiple conductor transmission lines abovea lossy earth

The current induced on an infinite multiple conductor transmission line located above a lossy homogeneous medium due to a transient plane wave is discussed. An exact solution is formulated in the frequency domain using a spatial transform technique. The widely utilized quasi-TEM approximation is derived directly from the exact solution with emphasis on the physical consequences of the assumptions made. Both frequency domain and time domain numerical results are presented for typical transmission structures and documented electromagnetic pulse (EMP) excitations. Comparison of the quasi-TEM approximation to the exact solution is made in order to study the validity of its application in EMP coupling problems. The modeling of the EMP source as an incident plane wave is examined by comparing the induced current due to a dipole source with its steepest-descent contribution     

纳秒激光耦合金属靶辐射电磁脉冲的实验研究

为了研究电磁脉冲(EMP)强度和分布与激光参量、靶体材料、结构等之间的关系,采用靶室内部的超小B-dot天线对强激光打靶过程中产生的电磁脉冲进行了测量,分析了不同辐射方位的脉冲强度,同时探讨了靶体支撑杆为绝缘体和导体两种情况下的电磁辐射行为。结果表明,不同方向和不同靶杆测得的电磁脉冲明显不同,如在法线方向的电磁辐射达到20V,导电靶杆最大达到22V的辐射,说明强激光打靶诱导的EMP具有很强的极化方向,并且在导体靶杆情况下,能够产生更强的电磁辐射。该研究有助于揭示激光打靶产生的EMP在靶室内部的传输极化特性以及其强度与靶杆导电性的关系。     

Scaling laws for coupling quantities on EMP

A set of scaling laws relating three-potential electromagnetic coupling quantities to three electromagnetic pulse (EMP) characteristics is derived. The electromagnetic coupling quantities are an attempt to characterize, in a very rough sense, the ability of an electromagnetic wave to induce an electronic upset in an electric circuit. The coupling quantities used are chosen based on voltage transients, power transients, and energy-induced overload as mechanisms for electronic upset. The independent quantities in the scaling laws are chosen to be the pulse rise time, peak field, and total energy density     

基于屏蔽暗箱窗口法材料快沿电磁脉冲屏蔽效能测试*

为满足材料强电磁脉冲场屏蔽效能的测试需求,搭建了基于屏蔽暗箱窗口法的材料电磁脉冲屏蔽效能测试系统.首先采用连续波对某种金属织物材料进行了频域测试,通过测试空箱和加载材料内部场强大小,计算了该材料的频域屏蔽效能.然后采用快上升沿电磁脉冲源对该材料进行了时域测试,计算了强场作用下材料的峰值屏蔽效能.对测得的时域信号进行降噪处理和快速傅里叶变换(FFT),得到了该材料频域屏蔽效能曲线,与频域试验所测曲线进行了对比,结果基本一致.实验表明该测试系统能够可靠评价强电磁脉冲作用下材料的屏蔽效能.     

一种用于电磁脉冲效应实验的计算机系统

设计了一种专门用来进行电磁脉冲效应实验的计算机系统。介绍了该系统的结构及工作原理。提出了故障重现的概念,分析了故障重现的实现方法。将该计算机系统用于电磁脉冲效应实验,观察到了多种故障现象,测出了故障阈值。实践表明,该系统是计算机电磁脉冲效应实验的有力工具。     

On the electromagnetic pulse produced by nuclear explosions

The electromagnetic pulse (EMP) produced by the gamma rays from nuclear explosions is discussed. The gamma rays produce a current of Compton recoil electrons, and these electrons produce further ionization so that the air becomes conducting. The Compton current leads to the generation of electromagnetic fields according to Maxwell's equations. The conductivity tends to limit the magnitude of the fields. Approximate methods of solving the equations are described by considering time regimes in which various terms in the equations are negligible, e.g., either the conduction current or the displacement current can be dropped. Further advantage is obtained by replacing the transverse fields by outgoing and ingoing waves; outgoing waves are dominant at early times. Features of the solutions are described for nuclear bursts at the ground surface and at high altitude. The history of EMP is reviewed briefly.     

纳秒级电磁脉冲发生器的研制与相关寄生参数研究

为研究瞬态电磁脉冲故障注入对集成电路芯片的影响及其故障机理,基于Marx发生器原理和MOSFET开关特性,研制了一个全固态纳秒级电磁脉冲发生器.基于提出的HSPICE软件仿真等效模型,分析了发生器电路主要寄生参数对MOSFET开关特性的影响,并建立了相应的数学模型,为电磁脉冲发生器的研制提供了设计指南.实验结果表明:建立的数学模型精度为96.7%;基于二级Marx电路的电磁脉冲发生器可产生幅值可调（0~100 V）、脉宽可变（200~2 070 ns）、最快下降沿为32 ns的脉冲信号;在电磁探头下方5 mm处的测试线圈上可测得1 600 mV的感应电动势,并可利用该感应电动势来对芯片引入故障.     

电磁脉冲对太阳电池的损伤效应研究

针对电磁脉冲对太阳电池造成的损伤效应,通过器件-电路联合仿真的方法,在建立硅太阳电池单元器件模型的基础上,分析研究了在阶跃脉冲电压的注入下,太阳电池性能的退化情况.结果表明:在电压幅值一定时,上升时间存在一临界值,当上升时间大于这一临界值时,太阳电池的性能退化是可恢复的,小于这一临界值时,太阳电池短路电流和开路电压将迅速衰减,填充因子也随之减小,电池部分失效甚至全部毁坏.在上升时间一定时,不同幅值的电压都会使得电池的短路电流和开路电压下降,但相对于开路电压,短路电流的下降并不显著,当电压幅值大于某一值时,开路电压下降趋于加快,随着电压幅值的不断增加,太阳电池将被击穿,从而完全失效.     

HEMP 传导型防护模块测试系统的设计与实现

依据GJB 3622-1999 标准,针对高空核电磁脉冲(HEMP)传导型防护模块的测试需求,设计了一套线-地脉冲电流耦合注入测试系统,完成了高空核电磁脉冲的产生、测量系统的搭建和射频EMP 保护器的测试。该系统脉冲上升沿tr ≤10 ns,脉冲半宽度500 ns≤ thw ≤550 ns,设计指标完全符合GJB 3622-1999 标准的要求。为测试方便,设计脉冲发生器中的高压源在0 ~50 kV 范围内人工调节,并实现了油绝缘火花隙开关遥控放电。测试系统采用电流探头(罗氏线圈)、电压探头、数字存储示波器等设备进行电流和电压的采集,利用所测数据计算出被测防护模块的电流抑制比(SEI),从而完成对传导型防护模块的性能测试以及毁伤阈值测试。本测试系统性能稳定,可靠性高,测试数据准确可靠,目前已经在工程实践中得到了广泛应用,取得了很好的效果。     

Predicting the breakdown behavior of microcontrollers under EMP/UWB impact using a statistical analysis

Reproducible prediction of damaging effects is one of the main problems in intentional electromagnetic interference (IEMI). In this paper, the susceptibility of different types of single microcontrollers to unipolar fast rise time pulses [electromagnetic pulse (EMP), ultrawide band (UWB)] is determined. Therefore, pulses with rise times as fast as 100 ps and electric field amplitudes of up to 100 kV/m are applied to the devices. The results are generalized with a novel statistical procedure. Following discussion and rationale, the Weibull distribution is selected to describe the interference behavior. The statistical analysis provides a new test procedure for a confident determination of the interference behavior parameters.     

Pulse response of linear dipole antenna

Applications of transient electromagnetics include nonnuclear electromagnetic pulse (EMP) effects on electronic systems to evaluate system vulnerability. A basic component used in the mathematical modeling of systems for EMP vulnerability is the linear dipole antenna. Wu has derived an approximate analytical solution for the pulse reflected from the feed point of a linear dipole antenna for an incident ideal step function of current. The solution does not include the part associated with the very high frequency components because of an approximation used in evaluating the integral describing the reflected pulse. The approximation is eliminated and a simple analytical solution is given that describes that portion of the step function response associated with the very high frequency components. Numerical evaluation of the solution demonstrates convergence with Wu's approximate solution.     

电磁脉冲弹及其防护

随着大功率微波器件的发展,大功率微波电磁脉冲弹(E-bombs)在国外已经实用化。由于其广谱、灵活、针对性强等特点,对通信、雷达、计算机网络等电子系统有极强的破坏能力。这里就电磁脉冲(EMP)的分类与特点、电磁脉冲弹的产生机理、电磁脉冲对电子系统的影响机理以及应采取的防护措施进行了讨论,重点讨论了通信系统的防护措施。     

A numerical method for transient analysis of coupled antennas

A numerical method for finding the transient response induced on coupled thin cylindrical antennas excited by an electromagnetic pulse (EMP) is introduced. Numerical examples are given for two coupled thin antenna that are broadside incident by an idealized EMP. Applications of the method are made to calculate the induced currents on corner reflector antennas, and numerical examples are given to illustrate how the transient responses are modified by coupling effects. Examples of applying the method to include the effects of the time-varying medium on the responses are also shown with an assumed time-varying air conductivity.     

HEMP模拟器的改进及测量探头的设计

针对国际电工委员会发布的高空核电磁脉冲（HEMP）波形新标准,对有界波电磁脉冲模拟器进行了改进：研制了新型纳秒液体开关,设计、制作了D-dot型电场监测探头,构成了一套完整的快前沿HEMP抗扰度实验系统。试验结果表明,改进后的模拟器可产生前沿小于2.0 ns,半峰宽25 ns,峰值50 kV/m的双指数电磁脉冲;通过与瑞士Montena公司生产的SEG2G型电场探头试验测量结果的比较,表明本文研制的测量系统完全满足设计要求。     

Transient radiation of traveling waves by wire antennas

A simple analytic method is suggested for calculating radiation fields from traveling current waves propagating along curvilinear wires. The solutions obtained are valid in both the near and the far zones. The results are used to calculate the radiation of linear and V-antennas, as well as those composed of rectilinear segments. The radiation of a wire placed over a conducting plane is calculated when the wire is an element of an electromagnetic pulse (EMP) simulator. An engineering method of EMP simulator design is put forward and justified     

New sensors for measuring very short electromagnetic pulses

In order to detect very short electromagnetic pulses under 100 ps in width, a wide-band receiving antenna with a bandwidth from 0 to 14 GHz is needed. The usual short dipoles or monopoles do not provide both the required fidelity (bandwidth) and sensitivity. A novel type of electromagnetic pulse (EMP) sensor has been designed, analyzed, and tested. It is simple, inexpensive, and can detect the electromagnetic pulse with both high fidelity and high sensitivity. An approximate analysis is given for better understanding and optimum design of the proposed EMP antenna