Double scatter vector-wave Kirchhoff scattering from perfectly conducting surfaces with infinite slopes

A double scatter Kirchhoff method for scattering of light from 2D perfectly conducting rough surfaces with high (infinite) slopes is presented. The method uses a variation of the traditional Kirchhoff approximation in which the surface normal is written in terms of the local surface differential increments. Example results are presented and it is shown that the calculations conserve energy when the surface sampling is adequate. The range of surface parameters for which energy is conserved for a single groove in a plane is found.