三维粗糙面散射中IRBC的FFT加速算法

对于粗糙表面等以平面结构为主体的散射问题，迭代Robin边界条件( IRBC )残值计算最耗时的部分是结构上方大范围的平面虚拟边界。为减少运算量,加快计算速度，将IRBC的积分方程转化为二维卷积形式，导出快速傅立叶变换加速计算的公式。通过有限元法数值模拟三维随机粗糙表面的电磁散射，验证了方法的精度与效率。

An FFT Accelerated Iterative Robin Boundary Condition for 3D Rough Surface Scattering

In the case of planar structure such as large-scale rough surface, most time consuming of the iterative Robin boundary condition (IRBC) evaluation is spent on the planar fictitious boundary. To reduce the computation complexity of the IRBC, a field integral equation is written as the 2-dimensional convolution form and gets solved efficiently by using the fast Fourier transform (FFT). The formulation of its mechanism is presented. And a simulation with finite element method of the electromagnetic scattering from 3-dimensional random rough surface is shown for the accuracy and efficiency.