An improved numerical simulation of electromagnetic scattering from perfectly conducting random surfaces

Numerical simulation of electromagnetic scattering from a one-dimensional perfectly conducting random surface is of interest, primarily for its application as a benchmark for evaluation of approximate theoretical models. Since rough surfaces are targets of infinite extent, approximations to the geometry or the formulation of the problem must be considered to make the numerical solution tractable. The standard method to suppress the edge effects of a finite surface sample is the tapered illumination approximation. This approximation is numerically inefficient because the effective illuminated width of the sample surface is much smaller than the physical surface width. The effect of the edges of the surface samples is minimized by controlling the conductivity of the surface near each edge by adding an appropriate tapered resistive sheet. It is shown that the scattering simulation based on the new technique is more efficient than the standard method. Also the backscattering coefficient predicted by the new technique is accurate for incidence angles as high as 80/spl deg/ while the angular validity range of the standard method is limited to 60/spl deg/.