Small slope approximation method: higher-order contributions for scattering from conducting 3D surfaces

The analysis presented in this paper focuses on the calculation of the scattering cross-section of randomly rough canonical three-dimensional objects. The scattering cross- section of objects is calculated by the Small Slope Approximation (SSA) method. The SSA method was suggested by Voronovich. The small parameter of the method, the roughness slope, differs from those used in classical approaches since it is independent of the incident electromagnetic wavelength. Second-order terms in SSA method have been implemented in order to obtain accurate results for a large range of slopes. Specific developments have been carried out for the TM case which presents a singularity. In this paper we discuss the theoretical SSA solution. Calculations are presented for both polarizations of the electromagnetic field. Numerical simulations with higher order contributions of SSA method and comparisons with published results will be discussed in this paper.