4m高度同轴馈电线栅型垂直极化EMP辐射波模拟器的辐射特性分析

Radiation Characteristics of Wire Vertically Polarized EMP Radiating-Wave Simulator Fed by Coaxial Transmission Line with 4 m Height

基于完全理想磁导体镜像的同轴馈电模拟器天线辐射场并行FDTD方法,研究了高度为4 m的同轴馈电线栅型垂直极化辐射波电磁脉冲模拟器的线栅截数、底部金属实体圆锥的高度、线栅的数目与半径、介质支撑圆柱及加载电阻对模拟器辐射场的影响。结果表明,模拟器设计时,选择线栅截数为1可消除线栅连接处对辐射场的不利影响;底部金属实体圆锥的高度越高,模拟器的辐射场越接近全部金属实体模型的辐射场;为保证模拟器的辐射场达到一定的电场强度峰值,底部金属实体圆锥必须达到一定的高度;当线栅数目在24~60变化时,距离中轴线4 m测点的电场强度峰值不小于全部金属实体模型时相应位置的电场强度峰值的93%;线栅半径在1.5~4 mm变化对模拟器的辐射场几乎没有影响;为减弱介质支撑圆柱对辐射场的不利影响,实验验收点不要选择在圆柱的对称面上,可选择在支撑圆柱对角线的延长线上;加载电阻可使某些测点的辐射场时域波形的半高宽变窄,模拟器的有效测试区域可能增大。

In this paper,a wire vertically polarized EMP radiating-wave simulator fed by coaxial transmission line with 4 m height is taken as a research object,and the perfectly ideal magnetic conductor(PMC)image method is applied to the parallel finite-difference time-domain(FDTD)calculation of the radiation field characteristics of the coaxial fed simulator.The influence of the wire-section’s number,the height of the metal solid cone at the buttom,the number and radius of the wire,and the dielectric supporting pillars of the simulator to the radiation fields to the simulator are studied.The results show that when the wire-section’s number is 1,the wire junction has no effect on the radiation field of the simulator,the higher the metal solid cone at the bottom is,the closer the radiation field of the simulator is to that of all the metal solid models.When the number of the wire varies from 24 to 60,the peak value of electric field intensity at the measuring point 4 m away from the central axis is not less than 93%of the corresponding position of all metal solid models.When the wire radius varies from 1.5 mm to 4 mm,it has little effect on the radiation field of the simulator.To reduce the adverse effect of dielectric supporting pillars on the radiation field of the simulator,the experimental acceptance point should not be on the symmetry plane of the supporting pillars,but on the extended line of the two pillars’diagonal.The resistance loading can narrow the FWHM of the time domain waveform of the radiation field at some measuring points,and increase the effective test area of the simulator.