NUMERICAL-SIMULATION OF SCATTERING FROM ONE-DIMENSIONAL INHOMOGENEOUSDIELECTRIC RANDOM SURFACES

In this paper, an efficient numerical solution for the scattering prob lem of inhomogeneous dielectric rough surfaces is presented. The inhom ogeneous dielectric random surface represents a bare soil surface and is considered to be comprised of a large number of randomly positioned dielectric humps of different sizes, shapes, and dielectric constants above an impedance surface. Clods with nonuniform moisture content ad d rocks are modeled by inhomogeneous dielectric humps and the underlyi ng smooth wet soil surface is modeled by an impedance surface. In this technique, an efficient numerical solution for the constituent dielec tric humps over an impedance surface is obtained using Green's functio n derived by the exact image theory in conjunction with the method of moments. The scattered field from a sample of the rough surface is obt ained by summing the scattered fields from all the individual humps of the surface coherently ignoring the effect of multiple scattering bet ween the humps. The statistical behavior of the scattering coefficient sigma degrees is obtained from the calculation of scattered fields of many different realizations of the surface. Numerical results are pre sented for several different roughnesses and dielectric constants of t he random surfaces. The numerical technique is verified by comparing t he numerical solution with the solution based on the small perturbatio n method and the physical optics model for homogeneous rough surfaces. This technique can be used to study the behavior of scattering coeffi cient and phase difference statistics of rough soil surfaces for which no analytical solution exists.