高阶基尔霍夫法求解导体粗糙表面的散射特性

在分析粗糙表面电磁散射特性的基础上,提出了一种考虑粗糙表面协方差函数Taylor展开的高阶基尔霍夫近似(KA)法,解决了经典KA近似的大逼近误差问题.应用9阶高度的KA和传统的KA,对比研究了不同照射频率和均方根高度下的后向散射系数,并比较了遮挡函数的修正效应.同时应用高、低阶KA计算了典型粗糙面的后向散射系数,并分别与测量值和矩量法的数值解进行了比较.结果表明,9阶表面高度展开的切平面KA不仅拓宽了KA的适用条件,还具有更高的精度范围,从而证明了高阶均方根高度展开的KA近似的有效性.

High-order Kirchhoff approach for electromagnetic scattering for perfectly conducting rough surface

On the basis of analyzing the scattering property from rough surface, a new high-order Kirchhoff approach for two-dimensional perfectly conducting rough surface considering the series expansion of root mean square height is presented. The problem of scattering error due to the approximation at low-order Kirchhoff is solved. The backscattering coefficients and shadowing modified effect is studied by making use of the ninth-order and first-order Kirchhoff approximation at different roughness and frequency. For an actual manmade rough surface, the backscattering coefficient is calculated by moment of method, low-order and high-order Kirchhoff approach, respectively. Comparing with a set of measured data, the numerical results show that the presented method is validity with a high precision in more extensive range.