贯穿设备屏蔽层线缆电磁脉冲响应研究

提出了一种获取电子设备壳体屏蔽层外接线缆电磁脉冲耦合响应的计算方法。首先,以壳体屏蔽层为分割点,将贯穿线缆分为内外两部分,根据基本传输线理论和戴维南等效原理,得到内外两段线缆的等效电路模型。然后,利用Agrawal散射电压模型分析了外等效电路的端口负载频域响应,并根据该负载响应得出了内部线缆等效电路的端口负载频域响应。最后,以高空核爆电磁脉冲的IEC标准波形为计算波形,通过傅里叶变换方法求解了内部端口上的时域响应,并分析了线缆几何参数和终端负载对响应波形的影响。     

高功率激光装置同轴线缆电磁脉冲耦合仿真

高功率激光装置开展实验会产生强烈的电磁脉冲辐射。电缆端口是电磁干扰耦合的重要途径。针对高功率激光装置上广泛使用的同轴线缆开展电磁脉冲耦合问题仿真研究,建立同轴线缆的电磁脉冲耦合仿真模型,研究不同入射方向、不同长度同轴线缆电磁脉冲耦合的感应电压。仿真结果显示,同轴线缆部署方向以及长度对电磁脉冲耦合具有显著的影响。本文对装置靶场线缆选型、线缆铺设以及诊断仪器电磁屏蔽设计有着参考价值。     

光学窗口的电磁耦合模拟和防护技术

当高功率微波（HPM）辐照装配光学窗口的电子方舱,电磁波将通过透明光学窗口耦合进入方舱内部,损伤方舱内部的电子器件。基于有限时域差分法（FDTD）,文章计算了点辐射源和平面波入射下舱体内部的场强分布,当窗口采用ZnS／Ag／ZnS多层透明导电薄膜防护时,屏蔽效能达到40dB,可对内部电子器件产生有效的防护。     

架空多芯电缆对高功率微波耦合特性研究

通过数值计算和试验研究地面附近有限长架空多芯电缆对高功率微波的耦合特性,为指挥工程中电缆耦合特性研究提供参考。数值计算和试验结果表明,架空多芯电缆对窄带高功率微波和超宽谱高功率微波具有耦合作用,不同芯线之间存在互耦,耦合特性受电缆接头处理方式、电缆长度、电缆类型、电缆与来波方向(极化方向)夹角、屏蔽层是否接地、微波频率等影响严重。数值计算和试验结果在规律上比较一致,证明了计算模型和试验方法的正确性和有效性。     

基于场积分方程的机箱耦合电流特性的数值分析

各种电子电器设备都有外接导线,例如通讯线、信号线、电源线等。虽然电子电器设备本身可以通过屏蔽体抵御外部的电磁干扰,但是外部的电磁干扰仍然可以通过暴露在屏蔽体外的导线直接将电磁能量耦合到蔽体内部,使屏蔽体内的电磁环境变得更加复杂。文章依据边界条件推导出电磁场积分方程,并通过矩量法计算了导线与机箱外壳连接点的感应电流强度,在导线的半径、入射电场的极化方向和导线间距等各种因素影响下,通过理论得出模拟曲线,发现耦合电流随频率的一些变化规律。     

不同带宽高功率电磁环境对架空线缆耦合效应分析

为分析典型高功率电磁环境对架空线缆的耦合效应,应用并行时域有限差分算法,计算了在雷电电磁脉冲和两种高空核电磁脉冲环境下架空线缆的外导体感应电流和终端电压波形,分析了不同线缆长度、不同入射波极化方向情况下架空线缆耦合效应的变化规律.研究结果表明：入射波电场方向与线缆方向一致时,耦合效应最为严重;随线缆长度增加,外导体感应电流和终端电压上升沿陡度不变,但峰值变大,波形变宽.当线缆长度增加到可与入射波能量最集中频段波长相比拟时,其峰值达到最大,变化趋于平稳,在频带偏低的LEMP作用下该长度在几千米以上,而HEMP1（贝尔波形）入射时为几百米量级,频带最宽的HEMP2（IEC 100029）则为几十米量级;在线缆和入射情况相同条件下,LEMP对线缆耦合效应最强,HEMP1次之,HEMP2最弱.     

一种线缆护套的屏蔽效能测试方法

设计了一种基于串扰理论的线缆护套屏蔽效能的测试方法,根据测试结果分析了屏蔽护套不同接地方式对线缆间感性耦合、容性耦合的影响,试验结果可为在实际工程中抑制线缆串扰提供依据。     

某高机动两坐标雷达高功率微波加固探讨

针对某高机动两坐标雷达，分析了高功率微波环境、耦合通道、加固总体思路等，对加固要求的确定、前门加固技术、后门加固技术进行了详细论述。用统计学分析的理论确定了雷达的加固要求，提出了高功率微波对雷达前门和后门的几种耦合形式，重点分析了滤波器和限幅器的正确使用、屏蔽、孔洞加固等内容。     

高功率微波脉冲对微带电路的影响

随着微波技术的不断发展,各种高功率微波武器相继产生,这些武器不但能起到电磁干扰的作用,而且还能够把电磁能量集中在很窄的脉冲内,直接摧毁电子设备.另一方面.近年来,微带电路以其体积小,重量轻,耗能少,可靠性高等优点在微波领域显示出强大的生命力,但是高度集成化的微波电路易受小量微波能量的影响.微波能量能够通过各种渠道耦合进入系统壳体,对电子器件产生破坏性的效应,使其失效或功能下降.利用FDTD方法分析了高功率脉冲照射下的微波集总元件电压变化的情况,并比较了在有无屏蔽盒保护作用下的影响结果,为下一步研究高功率微波脉冲对复杂微波电路的影响奠定了理论基础.     

近地电缆屏蔽层对高空核电磁脉冲响应的研究

为了研究近地面电缆屏蔽层对高空电磁脉冲的耦合规律,依据传输线理论,计算了在高空核电磁脉冲作用下损耗大地上电缆屏蔽层上的感应电流。利用快速傅立叶变换技术,首先得到近地面电缆屏蔽层感应电流的频域解,然后采用快速傅立叶逆变换技术得到时域解。得到了感应电流随电缆长度、电缆架设高度、电磁脉冲极化角、方位角、俯仰角、端接阻抗和大地电导率等的变化规律。     

贯通导线对屏蔽机箱内电路HEMP耦合电流的影响

应用时域有限差分法，研究了屏蔽相箱上贯通导线对机箱内电路HEMP耦合电流的影响，研究表明，贯通导线通过与入射场及屏蔽机箱的散射场耦合，可使机箱内与贯通导线直接相连或不相连电路上的HEMP耦合电流显著增强，此研究对电台、微机等电子设备和系统的核电磁脉冲防护具有十分重要的意义。     

Transmission Line Mode Response of a Multiconductor Cable in a Transient Electromagnetic Field

This paper describes a technique for obtaining the induced worst case currents on individual wires of a multiconductor cable as a result of a transient electromagnetic radiation field. The technique involved a development of the expression for the induced current in matrix form where the mutual coupling terms and the other cable currents are the pertinent parameters. A worst case solution results from the assumption of maximum coupling orientation of the individual wires. A short example and some test results are presented. The test results show wave shapes for inductive and capacitive coupling. The solution for the individual wire current due to a transient electromagnetic field is important, since it will greatly reduce the required number of cable measurements and will allow the development of improved shielding techniques.     

Performance optimization of critical nets through active shielding

We propose the concept of active shields-shields that switch concurrently with a signal wire of interest. Active shields aid signal transitions through the coupling between the signal wire and shields. For RC dominated wires, the active shields switch in the same phase as the signal wire since capacitive coupling is the dominant coupling mechanism. For wires with dominant inductive coupling, active shields switch in the opposite phase of the signal wire. We show that under fixed area and input capacitance constraints, in-phase active shielding outperforms traditional (passive) shielding and wire sizing/spacing techniques for minimizing delays and transition times on RC-dominated wires. For RLC wires, we demonstrate a region of feasibility (in terms of signal wire widths) for which opposite-phase active shielding outperforms the passive shielding technique. Opposite-phase active shielding suppresses ringing behavior to a greater degree than passive shields, providing similar performance to differential signaling while maintaining the simplicity of single ended signaling. The benefits of opposite-phase active shielding as compared to passive shielding are shown in the context of various clock net optimizations where reductions in ringing behavior (up to 4.5X) and transition times (up to 40% reduction) are achieved.     

多芯屏蔽电缆屏蔽效能的脉冲电流注入法测量

为了测量脉冲电流注入电缆的时域屏效,采用皮电流I0与短路芯电流Id峰峰值之比的分贝数求解电缆的屏蔽效能方法,给出了某百芯屏蔽电缆的等效电压源内阻和屏蔽效能值,并对外场辐射试验法中的某百芯初样电缆总的屏蔽效果进行了计算和讨论。     

含贯通线及PCB板开孔腔体的电磁耦合研究

外界能量通过贯通线进入开孔屏蔽体,与PCB上MSL耦合而生成感应电流(Current),加剧了对敏感器件的耦合伤害。故建立含贯通线及PCB板开孔屏蔽腔模型,进行多角度耦合特性计算。在建模有效性验证后,利用有限元法探讨平面波激励下PCB不同模型、MSL上不同端接电阻、贯通线半径、贯通线与腔体壁相接及多贯通线等参数变化对Current的影响规律。结果表明:双介质模型的使用更接近实际PCB 结构对场的影响;两端接电阻取值相差不大条件下,可不考虑与MSL的阻抗匹配,取值也可不相等;Current 数值随贯通线半径的增加而增加;贯通线与腔体壁不同表面相接对应Current幅值要远高于非接触的情况,并会激出新的谐振点。多根贯通线及线间距改变时Current幅值都要高于单线的情况,尤以第一谐振之前更为明显,多线存在不会影响谐振点出现位置。     

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     

Study of the magnetic coupling between a SQUID and wires integratedon a chip

Magnetic coupling between a SQUID and wires in an integrated circuit has been studied. Using test integrated circuits, the coupling is measured by varying the distance from the SQUID to each wire. The coupling between the SQUID and the wires with and without a groundplane decreases with an increase in the distance. The coupling for the wires with the groundplane is smaller than that for the wires without the groundplane at distances less than 595 μm. However, the rate of the decrease in the coupling for the wires with the groundplane falls off for distances more than 595 μm and the coupling converges to around 2.9 pH. From two dimensional simulations for the magnetic flux coupling, the origin of the residual inductance is found to be the coupling between the SQUID, and shielding current in the groundplane. The value of the distance, 595 μm, does not depend on the size of the SQUID. To decrease the coupling, the use of wires with stripline structure or coplanar structure is desirable     

不完全屏蔽腔体辐射耦合电场增强效应防护方法

针对武器装备机箱内部电磁辐射防护的技术需要,从不完全屏蔽腔体辐射耦合电场增强效应形成机理出发,对孔缝耦合及贯通导体耦合导致的屏蔽腔体内部局部电场增强效应防护方法进行了研究.仿真计算了屏蔽腔体内部加载吸波材料、腔体分区隔断以及贯通导体安装金属导管等防护方法对不完全屏蔽腔体电磁耦合的影响,研究结果表明:在屏蔽腔体内部加载吸波材料能够有效降低由于腔体谐振产生的电场增强效应,相同的吸波材料放置在强场位置防护效率会更高;采用分区隔断的屏蔽腔体能够提高腔体的谐振频率,大幅降低腔体内大部分位置的电磁耦合能力;贯通导体通过金属导管进入屏蔽腔体能够有效降低贯通导体的电磁耦合能力,削弱屏蔽腔体内部的电场增强效应,屏蔽腔体内部及外部的金属导管长度越长,其防护效果越明显.     

FDTD modeling of common-mode radiation from cables

Radiation from cables attached to printed circuit boards and shielding enclosures is among the primary concerns in meeting FCC Class A and B limits. The finite-difference time-domain (FDTD) method can be employed to model radiation from printed circuit boards and shielding enclosures with complex geometries, but difficulties in modeling wires and cables of arbitrary radii are encountered. Modeling the wire by setting the axial component of the electric field to zero in the FDTD method results in an effective wire radius that is determined by the mesh discretization. Neglecting the wire radius in applications, such as electromagnetic interference (EMI) or printed circuit board modeling, may result in gross errors because near-field quantities are typically sensitive to wire thickness. Taflove et al. (1988) have developed a subcellular FDTD algorithm for modeling wires that has been shown to work well for plane wave scattering. The method uses a quasistatic field approximation to model wires with a well defined radius independent of the mesh dimensions. The wire model is reviewed and investigated for application to common-mode radiation from cables attached to printed circuit boards, where the source is often a noise voltage at the connector. Also investigated is energy coupling to attached cables through enclosure apertures resulting in common-mode radiation from the cable. The input impedance for a center-fed dipole antenna, as well as a monopole connected to a conducting half-sheet, is computed with FDTD methods and compared to moment method input impedance results. A simulation of a shielding enclosure with an attached cable demonstrates the utility of FDTD analysis in modeling common-mode radiation