EM Wave Scattering by Random Surfaces With Different Contrast and Large Roughness Heights

A solution for electromagnetic (EM) scattering over a two-dimensional random rough surface (three-dimensional scattering problem) with large roughness height using the generalized functions approach is proposed in this paper. The EM field derivation incorporates rough surface profile with small-slope, a radiation source and involves all scattering orders of the scattered electric field (E-field) for high and moderate contrast media. Subsequently, the first-order scattered E-field is calculated using the Neumann series solution for transverse magnetic (TM) polarization. By considering pulsed dipole antenna and a two-dimensional Gaussian rough surface distribution with different root mean square heights and correlation lengths, the scattered E-field along with the radar cross-section is calculated. Using the result of the method of moments (MoM) as reference, a numerical evaluation of the solution for different roughness heights and contrast media demonstrates that the proposed solution is better than those of the small perturbation method (SPM), Kirchhoff approximation (KA) and small-slope approximation (SSA).