具有二维fBm特征的分层介质粗糙面电磁散射的特性研究

运用微扰法研究了平面波入射分层介质粗糙面的电磁散射，推出了不同极化状态下的双站散射系数公式.采用二维fBm分形粗糙面来模拟实际的分层介质粗糙面，结合二维fBm分形粗糙面的功率谱导出了平面波入射二维fBm分形分层介质粗糙面的散射系数计算公式.通过数值计算得到了HH极化下双站散射系数随散射角的变化曲线，讨论了分维、底层介质介电常数、中间介质介电常数和厚度及入射波频率对双站散射系数的影响，得到了二维fBm分形分层介质粗糙面散射系数的分维特征、基本特征、分区特征和随频率变化的特征. 关键词： 电磁散射 二维fBm分形粗糙面 分层介质 微扰法

Investigation on the characteristics of electromagnetic scattering from 2-D fBm rough surface of layered medium

The electromagnetic scattering from the rough surface of layered medium with plane wave incidence is investigated. A 2-D fBm fractal rough surface is used to simulate the natural rough surface of layered medium, and the formulae of the scattering coefficient of the 2-D fBm fractal dielectric rough surface of layered medium with the plane wave incidence is derived by using the small perturbation method in association with the power spectrum density of 2-D fBm fractal rough surface. The angular distribution of the bistatic-scattering coefficient of HH polarization are obtained by numerical computation, the influence of fractal dimension, the permittivity of substrate medium, the permittivity and the mean layer thickness of intermediate medium, the surface roughness parameters and the frequency of the incident wave on the bistatic-scattering coefficient is discussed. The fractal characteristics, the basic characteristics, the zonal characteristics and the characteristics with varying frequency of the scattering coefficient from 2-D fBm fractal rough surface are obtained.