Scattering of Electromagnetic Waves From Rough Surfaces: A Boundary Integral Method for Low-Grazing Angles

Abstract

Abstract-We present a boundary integral method for the numerical solution of the rigorous problem of wave scattering from rough surfaces under grazing illumination. The model of a locally perturbated plane is adopted: a finite patch of rough surface has its roughness flattened at the edges. The boundary formulation unknowns are the tangential components of the scattered field, defined as the contribution from the rough area. This way, the numerical domain of study is correctly bounded, even with a plane wave as incident field, and the sampled area is made independent of the incidence. This rigorous approach, called the grazing method of moments, is implemented on two-dimensional perfectly conducting surfaces and validated by comparison with a reference numerical solution for surfaces with Gaussian correlation functions. Now, the validity of approximate models at low-grazing-angles can be investigated; the small perturbation method and the small slope approximation are addressed in this paper. Scattering diagrams show how the performances of these methods deteriorate drastically at backward scattering angles as the incidence goes to grazing.

Inverse Wave Scattering of Rough Surfaces With Emitters and Receivers in the Transition Zone

“…However, localized sources in the vicinity of the surface do not radiate tapered waves. In this paper, the locally perturbated plane approach [19] was implemented to curcumvent this obstacle. Solving the inverse scattering problem consists in determining the best estimate of the actual profile from its scattered field.…”

“…Finally, our approach is not limited to two-dimensional scattering. Numerical solutions for the forward problem on two-dimensional surfaces can be coupled to the locally perturbated plane approach [19]. However, with antennas on a grid and a two-dimensional surface, the size of matrix D in the iterative process (Section 3) turns so large that specific numerical developments are to be planned.…”

“…This is a way to avoid the unphysical scattering from the edges of the sampled surface. In this paper, another approach is followed [19], where the rough surface is a local deformation of a plane. Stability and convergence of this finite section method when the roughness becomes non-local was studied in [20].…”

Study of Backscatter Signature for Seedbed Surface Evolution Under Rainfall --- Influence of Radar Precision

“…Function b(x, y) is obtained by filtering of a Gaussian white noise (see Section 3.3). Function w(x, y) is a weighing window having continuous first and second derivatives [5][6][7]22]. Function w(x, y) is equal to zero outside the domain |x| , |y| > L/2 and equal to 1 within the domain Table 5.…”

Rigorous Simulations of Microwave Scattering From Finite Conductivity Two-Dimensional Sea Surfaces at Low Grazing Angles

“…An alternative numerical approach where the boundary conditions are left untouched has been proposed by some of the authors in [13]. In the cited paper, it is described how edge effects can be avoided, whereas the incident field consists in a polarized plane wave.…”