Analysis of scattering from very large three-dimensional rough surfaces using MLFMM and ray-based analyses

Abstract

Several techniques are considered for the analysis of electromagnetic scattering from rough ocean surfaces. A rigorous Multi Level Fast Multipole Method (MLFMM) i� employed, as well as a high-frequency ray-based solution. The MLFMM analysis is implemented in scalable form, allowing consideration of scattering from very large surfaces (in excess of 100,4, x lOOk, where ,4, represents the electromagnetic wavelength). Plane-wave incidence is assumed, and a key aspect of the MLFMM study involves investigating techniques' for rough-surface truncation. The rough surface is modeled as a target placed in the presence of an infinite half-space background; to minimize edge effects, the surface is smoothly tapered into the planar half space. We also consider the technique of employing a resistive taper on the edges of the rough surface. These two truncation techniques are compared in accuracy, memory requirements (RAM), and in computational time (CPU). The MLFMM results are used to validate an approximate ray-based high-frequency model that allows rapid analysis of large surfaces. The computational results are compared to measured forward-scattering data from scaled laboratory measurements, used to simulate scattering from an ocean surface.

Composite Scattering from an Arbitrary Dielectric Target above the Dielectric Rough Surface with FEM/PML

“…The analysis of electromagnetic scattering from a target above the rough surface has developed into a very important issue in the electromagnetic theory, which can be applied in electromagnetics, remote sensing, target recognition, oceanography, etc. In the past several decades, many methods have been introduced into the studies on the electromagnetic scattering from the composite model, such as the finite element method (FEM), [1] the method of moment (MoM), [2] the fast multiple method (FMM), [3] the forward-backward method (FBM), [4,5] and the finite difference time domain method (FDTD). [6] Many valuable papers have been contributed to studying the scattering properties of a target above the rough surface in some important publications and journals.…”