电磁散射在层状空间目标的FDTD计算

FDTD on electromagnetic scattering from layered space target

研究用于分析层状空间目标电磁散射特性的时域有限差分(FDTD)方法。从二维Maxwell方程出发,导出带有入射角的一维修正Maxwell方程组及辅助方程,来计算二维总场-散射场(TF/SF)垂向边界上电磁场,从而在层状空间中实现直接时域形式的均匀平面波入射;为避免复杂的Sommerfeld积分,用互易原理得到简化的外推算法。用该方法对半空间目标电磁散射场和层状有耗空间中的线电流辐射场进行计算,在半空间近场区域得到了良好的均匀平面波,并且远场与已有文献结果和解析解结果都吻合较好,表明本算法和程序是正确和有效的。用该算法对多层状空间中的隧道、隧道内通车辆等目标以及隧道和车辆在无耗层状空间中的电磁散射特性进行研究。结果表明,金属车体对远区散射场贡献较大,且介质层的损耗特性影响着其对车体的屏蔽能力。

The method of analysis of layered space target electromagnetic scattering characteristics of the finite difference time domain（FDTD）is applied in this study.First embarks from the two-dimensional Maxwell＇s equation,derived with incident Angle of one-dimensional correction Maxwell＇s equations and auxiliary equation,to calculate the two-dimensional PLD-scattering field（TF/SF）electromagnetic field vertical boundary,in order to implement directly in a layered space time domain in the form of a uniform plane wave incidence;To avoid complex Sommerfeld integrals,with principle of reciprocity to get a simplified calculation method.With the above method then half space target electromagnetic scattering field and the line current in layered lossy space through the calculation of the radiation field in the half space near field region is uniform plane wave,and the far field with existing literature results and analytical solutions are very good match,shows that this algorithm and program are correct and effective.At the end,the algorithm for multilayer shape space vehicles,such as the target of tunnel,tunnel and the tunnel and vehicles in the absence of layered space to study the electromagnetic scattering characteristics of consumption.The results show that the larger contribution to the scattering field of metal car body to far area,and the wastage of the dielectric layer features affects its shielding ability of body.