Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application

We constructed a compact high-power RF pulse generator based on a gyro-magnetic nonlinear transmission line(GNLTL) to produce a high-voltage pulse with a sub-nanosecond rise time and a relatively high repetition rate, which shows great potential for application in the high-power ultrawideband electromagnetic effect, etc. The influence of incident pulse parameters(rise time and voltage amplitude) and line length on the sharpening characteristics of the GNLTL were investigated experimentally to optimize the rising rate of the modulated pulse front. Based on the GNLTL equivalent circuit model consisting of an LC ladder network, the rise time, the voltage conversion coefficient and the rising rate properties of a modulated pulse were also numerically analyzed in a wider range. The results show that a?>?90 k V RF pulse with a rise time of 350 ps and a repetition rate of 1 kHz in burst mode is produced by the GNLTL at an axial biasing magnetic field of 22 kA m^-1 and a line length of 30 cm under the condition of a 70 kV incident pulse. Applying a faster and higher incident pulse is conducive to improving the sharpening effect of the GNLTL. Furthermore, within a certain range, increasing the line length of the GNLTL not only reduces the rise time, but increases the voltage conversion coefficient and the rising rate of a modulated pulse. Furthermore, considering the energy loss of ferrite rings, there is an optimal line length to obtain the fastest rising rate of a modulated pulse front edge.

Investigation of an X-band magnetically insulated transmission line oscillator

An X-band magnetically insulated transmission line oscillator （MILO） is designed and investigated numerically and experimentally for the first time. The X-band MILO is optimized in detail with KARAT code. In simulation, the X-band MILO, driven by a 720 kV, 53 kA electron beam, comes to a nonlinear steady state in 4.0 ns. High-power microwaves （HPM） of TEM mode is generated with an average power of 4.1 GW, a frequency of 9.3 GHz, and power conversion efficiency of 10.870 in durations of 0-40 ns. The device is fabricated according to the simulation results. In experiments, when the voltage is 400 kV and the current is 50 kA, the radiated microwave power reaches about 110 MW and the dominating frequency is 9.7GHz. Because the surfaces of the cathode end and the beam dump are destroyed, the diode voltage cannot increase continuously. However, when the diode voltage is 400 kV, the average power output is obtained to be 700 MW in simulation. The impedance of the device is clearly smaller than the simulation prediction. Moreover, the duration of the microwave pulse is obviously shorter than that of the current pulse. The experimental results are greatly different from the simulation predictions. The preliminary analyses show that the generations of the anode plasma, the cathode flare and the anode flare are the essential cause for the remarkable deviation of the experimental results from the simulation predictions.

An Approach towards Pulse Data Transmission Using Modified Negative Luo Converter (MNLC) for Telecoms

Telecom sectors generally operate at negative voltages to reduce the effect of corrosion caused in the metallic wire due to electrochemical reaction while communicating signals. To feed those lines and to have an effective digital data transmission, a power electronic converter referred as Modified Negative Luo Converter (MNLC) is proposed in this paper. MNLC is a high gain converter in which the output voltage increases in geometric progression. This paper portrays a novel concept of a 50 Hz pulse data transmission through RLCG (Resistance-inductance-capacitance with a shunt conductance) transmission line using MNLC. Signal frequency of 50 Hz to be transmitted is anded with a high frequency pulse that charges and discharges MNLC and produces the boosted negative output voltage. The boosted output is again transmitted through the RLCG transmission line from which 50 Hz data pulse is retrieved at the output of the transmission line by comparing with a comparator signal. This sort of MNLC aided data transmission not only introduces less loss in its transmitted data but also overcomes various health hazards of conventional radio frequency (RF) communication. This technique also proves that any data bit stream can be transmitted and retrieved using the proposed high gain DC-DC converter. The simulation model of the proposed system is implemented in MATLAB for various switching frequencies with its prototype of the converter developed and the results are verified.

Numerical Analysis of the Output-Pulse Shaping Capability of Linear Transformer Drivers

Output-pulse shaping capability of a linear transformer driver （LTD） module under different conditions is studied, by conducting the whole circuit model simulation by using the PSPICE code. Results indicate that a higher impedance profile of the internal transmission line would lead to a wider adjustment range for the output current rise time and a narrower adjustment range for the current peak. The number of cavities in series has a positive effect on the output- pulse shaping capability of LTD. Such an improvement in the output-pulse shaping capability can primarily be ascribed to the increment in the axial electric length of LTD. For a triggering time interval longer than the time taken by a pulse to propagate through the length of one cavity, the output parameters of LTD could be improved significantly. The present insulating capability of gas switches and other elements in the LTD cavities may only tolerate a slightly longer deviation in the triggering time interval. It is feasible for the LTD module to reduce the output current rise time, though it is not useful to improve the peak power effectively.

基于分段线性模型针对TLP瞬态干扰信号的芯片协同防护设计方法研究

集成电路芯片在高密度、小型化发展过程中产生了电磁兼容问题,为强化集成电路芯片对瞬态干扰信号的应对防护效果,可结合传输线脉冲(TLP)测试构建分段线性模型。文章首先对芯片应对瞬态干扰信号展开防护设计的现实需求进行分析,以CD4001BE芯片为例提出芯片TLP测试分段线性建模方式,总结瞬态电压抑制TVS二极管建模方法,并进一步展开芯片分段线性模型协同防护设计分析,旨为借助分段线性模型的方式控制芯片防护的设计时间与成本。

ESD防护器件HMM和TLP测试方法及性能评价

人体–金属模型波形(HMM)和传输线脉冲(TLP)波形是静电放电防护器件测试时常用的注入波形。针对静电放电(ESD)防护器件,介绍了这2种波形的测试方法。通过对同一型号瞬态电压抑制器进行测量,获取器件的瞬态波形、钳位电压、损伤阈值、瞬态阻抗等特性参数,并对结果进行分析比较。测试结果表明,基于IEC标准的HMM测试所能得到的有效信息最少;基于TLP的HMM测试可直观得到被测器件的静电放电瞬态响应;TLP矩形波测试结果的稳定性好,测量参数的可重复性高。

Influences of Switching Jitter on the Operational Performances of Linear Transformer Drivers-Based Drivers

A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.

DETECTION OF PRIMARY TISSUE FAILURE POTENTIAL OF BIOPROSTHETIC HEART VALVES IN A STERILE PULSE DUPLICATOR SYSTEM

This paper discusses results of anatomic analogy and transmission line model for designing a sterile pulse duplication system for bioprostheses. By simulating physiological flow and pressure pulses as well as the input impedance of the human arterial system Pulsatile function testing allows us to study the hydrodynamic performances and the leaflet action of each valve. This inspection enables us to identify and reject those valves exhibiting leaflet prolapse or lazy leaflet or others believed to contribute to Primary tissue failure. Consequently, the risk of valve complications is reduced

一种基于TLP输入的系统级ESD模型分析方法（英文）

基于已有的传输线脉冲发生器(TLP)与IEC 61000-4-2应力的等效关系,提出一种以TLP应力作为输入的系统级模型分析方法。与传统的IEC应力作为系统输入的分析方法相比,该方法解决了对流入待测器件(DUT)残余能量的计算不够精确的问题,同时提高了DUT失效预测方面的精准性。通过SPICE仿真,预测了上述两种应力作为系统输入的DUT失效情况。通过相应的印制电路板(PCB)的实测验证,进一步说明新提出的方法能够提高系统级失效预测的精准性。

基于高分子电压诱导变阻膜的全PCB抗脉冲防护

随着芯片集成度的不断提高,内部互连导线间距越来越小,器件更易在静电作用下受到损害。为提高印制电路板(PCB)在实际应用中抗静电放电(ESD)和电磁脉冲(EMP)的能力,制作了一种高分子电压诱导变阻膜,将其嵌入PCB中形成脉冲吸收网络,使全板具备抗瞬变脉冲能力,实现对ESD和EMP的全系统防护。ESD防护实测结果表明,对比普通PCB,全抗脉冲PCB对静电脉冲有更快的响应速度和更高的释放效率;传输线脉冲(TLP)测试结果表明,采用电压诱导变阻膜的PCB中每一点都具有过电压脉冲吸收能力,电流泄放能力可达50 A以上。

工频下导线单雨滴电晕全过程分析

输电线路电磁环境问题主要由电晕放电引起,而降雨等环境变化会加剧这一现象。该研究通过高速摄像与电晕电流测量同步测量技术,详细分析工频下导线单雨滴电晕全过程。结果表明,导线单雨滴电晕全过程可分为4个阶段,尖端放电与振动破碎放电为主要放电类型,且两种放电的上升时间及半波时间概率密度分布均服从正态分布。随电压升高,尖端放电次数占比先减小后增大,电流脉冲幅值、上升时间、半波时间呈上升趋势;振动破碎放电次数占比先增大后减小,电流脉冲幅值、上升时间呈上升趋势,半波时间呈先上升后下降趋势。雨滴半径的增大对不同放电类型的放电次数和电流脉冲特性也产生一定的影响。该研究为理解雨天输电线路的电晕损耗和可听噪声变化提供新的视角。

旋磁非线性传输线原理分析和初步实验

作为一种特殊的宽带高功率微波源,旋磁非线性传输线(gyromagnetic nonlinear transmission lines,GNLTL)由于中心频率高、易于调频以及可以高重频运行等特点,得到了广泛的关注。为明确GNLTL的特殊工作机理,对比分析GNLTL与传统旋磁应用场景的不同之处。从微观磁化动力学入手,针对GNLTL产生微波的原因进行定性解释。搭建一套低功率的验证实验装置,重点针对实验场景构建、GNLTL设计进行介绍。实验得到微波信号的中心频率为750 MHz,3 dB波束带宽达12%,峰值功率为245 kW,初步验证了GNLTL的微波产生效果。

铁氧体传输线电压测量用自积分电容分压器设计

为了研究铁氧体传输线对脉冲前沿的陡化机理,研制了6个耦合式自积分电容分压器测量传输线不同位置的电压波形,以此来分析脉冲前沿的陡化过程。首先通过Pspice建立电容分压器的等效电路模型,从时域和频域上分析了同轴信号电缆匹配方式及低压臂补偿电容的杂散电感对电容分压器测量输出的影响,提出采用多个电容并联的PCB同轴结构减小其杂散电感对脉冲高频振荡的影响,然后根据传输线结构设计了一种低杂散电感的耦合式电容分压器,通过Comsol仿真计算出高、低压臂电容值并推导了理论分压比。实验测试了电容分压器工作于D-dot模式和自积分模式时的输出信号,对分压器的分压比及响应时间进行定标,结果表明所研制的电容分压器,实测分压比与理论值接近,响应时间约为2.1 ns,实现了6级铁氧体传输线不同位置的脉冲电压的同时测量。

基于铁氧体传输线的百纳秒脉冲前沿陡化技术研究

基于铁氧体传输线脉冲陡化原理,利用COMSOL软件建立了铁氧体传输线的电磁场仿真模型,研究了脉冲陡化的影响因素及特征规律,根据仿真模型设计了2种不同直径磁芯的铁氧体传输线,并建立了实验测试平台,对传输线陡化后的脉冲前沿进行测试。仿真及实验结果均表明,铁氧体传输线陡化后的脉冲前沿随输入电压幅值、传输线长度的增加而减小,随磁芯直径的减小而减小,实验结果与仿真结果规律一致。磁芯直径为40 mm,线长为1500 mm的铁氧体传输线可将幅值为120 kV的脉冲电压的前沿由124 ns陡化至14.4 ns,整个脉冲源的抖动为1.83 ns,验证了铁氧体传输线替代FLTD触发器中气体陡化开关的可行性。

非线性传输线产生射频脉冲原理研究

介绍了非线性传输线的工作原理和色散特性,给出了用于模拟交叉耦合磁饱和非线性传输线的计算方法。算法基于传输线各节点的时域差分方程组进行步进迭代,其中利用J-A模型描述传输线中NiZn铁氧体磁芯的非线性磁化行为,并模拟了非线性传输线的工作方式。实验获得了中心频率165MHz的宽带脉冲输出,初步验证了用于产生宽带电磁脉冲的非线性传输线关键技术。

瞬态电压抑制器在快上升沿电磁脉冲作用下的瞬态响应

为了研究瞬态电压抑制器(TVS)对快上升沿电磁脉冲的响应,基于传输线脉冲(TLP)测试理论,建立了由高频脉冲发生器、同轴电缆、专用测试夹具、30dB脉冲衰减器和高性能的数字存储示波器等组成的测试系统。参考时域传输(TDT)TLP测试方法,利用该测试系统,对典型双极TVS器件在快上升沿电磁脉冲作用下的电流特性和电压特性进行了研究,并对试验数据进行了拟合分析。结果表明,TVS器件的箝位电压、峰值电流等参数均随着测试电压的增大而增大,且与测试电压呈线性关系;而由箝位电压决定的箝位响应时间受测试电压的影响较小。经对比分析实验结果得出,对快沿电磁脉冲,采用固定响应时间下的箝位电压来衡量TVS器件的防护性能是较为合理的。

核电磁脉冲环境中传输线的电磁干扰

高空核电磁脉冲环境将在传输线上产生电磁干扰,会威胁与之相连的电子设备的安全。为了在理论上对传输导线在核电磁脉冲环境下的响应电流进行分析从而得到电流的响应规律,采用传输线计算模型,在电磁脉冲环境为正入射,地面为有耗介质时,计算了地面附近平行铺设的导线在两端短路、两端接高阻、一端接地一端接电阻、两端接不同电阻等4种状态下的电流响应;并研究了感应电流的幅值、上升沿、半高宽以及电阻上电压降等参数在导线长度增加时的变化情况,结果表明这些参数随传输线长度的变化均有最大值,而且电流幅值随传输线离地高度降低趋于减小。

架空配电线路雷电感应过电压计算研究

为了研究雷电感应过电压特性,指导架空配电线路雷电防护,分析了现有雷电感应过电压计算方法的不足,提出一种改进计算方法。该计算方法分为雷电电磁脉冲计算和雷电电磁脉冲激励下的多导体瞬态响应计算2个步骤,考虑了大地损耗对雷电电磁脉冲和多导体传输线瞬态过程的影响以及线路带有分支和集中参数元件的实际情况。通过与火箭引雷感应过电压实测波形的对比验证了计算方法的有效性。利用该文的计算方法对雷电感应过电压进行了计算分析,其基本特征表现为:雷电感应过电压为短尾波,在导线上距离落雷点最近处最大,并延导线逐渐衰减;大地损耗越大,最大雷电感应过电压值越大,但沿线衰减越快;雷电感应过电压的最大幅值受雷电回击速度的影响较小,受线路分支影响明显,同时与线路高度、线路与落雷点间距离为非线性关系。

脉冲功率装置中电容分压器的设计和应用

为了测量脉冲功率装置形成线和传输线的电压,设计和标定了自积分电容分压器和V-dot探测器。在电容分压器结构设计中,重点叙述了降低结构电感、削弱局部高电场以及保持灵敏度一致的方法。电容分压器采用在线标定,标定用电阻分压器安装在电容分压器相对于轴线对称的位置,以减小对探头位置电场分布的影响。对阳加速器水传输线、脉冲形成线和PTS单路样机中储探测器的标定和实验结果表明:无论是自积分电容分压器还是V-dot探测器,只要取值合适,同时在结构设计中注意分布参数的控制,就都可以响应前沿为几十ns至接近μs量级的信号。