电磁脉冲对金属板搭接缝隙耦合效应分析

Analysis on coupling effects of EMP into lapped joints in conducting screens

针对在缝隙耦合研究中,对金属板接合处搭接缝隙电磁特性的讨论相对较少的情况,应用时域有限差分方法模拟了强电磁脉冲对搭接缝隙的耦合穿透过程,计算了缝隙口径面等效面磁流和进入另一空间的透射场。为便于由等效磁流外推透射场,应用等效原理将电磁流在1/4空间的辐射等效为电磁流及其镜像在自由空间的辐射,避免了计算搭接缝隙边界情形下空间格林函数的困难。外推时采用分区外推法节省了计算时间。最后通过分析耦合场的变化曲线,总结了耦合共振规律。

In this paper, the coupling and penetration of electromagnetic pulse through lapped joints in conducting screen are simulated by the finite difference time domain （FDTD） method. Equivalent electromagnetic current sheets on the aperture and the transmission field are computed. For obtaining the far zone transmission field easily, the radiation of equivalent electromagnetic current sheets in a quarter-space is replaced by the radiation of equivalent electromagnetic current sheets and their images in free space based on the equivalence principle. This equivalent scheme avoids the difficulty of computing the Green＇s function with the boundaries of lapped joints. During extrapolating, sub-area extrapolation is applied which saves much computing time. Finally, by analyzing the variation of coupling field, the coupling resonant characteristic through lapped joint is obtained.