Numerical simulation of scattering from three dimensional randomly rough surfaces

Randomly rough surface patches in three dimensions are generated on the computer. The FD-TD method is used to compute scattering from surface patches by converting the Maxwell's equations into difference equations using a second-order central difference approximation for the space and time derivatives. The volume of grids above the rough surface is divided into the total field and the scattered field regions. In between these two regions, obliquely incident waves are generated. To reduce computation, the volume of grids is chosen to be small and hence a transformation is needed to convert the scattered fields into far zone fields for scattering coefficient calculations. Very good agreements are obtained between the results obtained by this method and those by a rough surface scattering model.<>