In the domain of electromagnetic wave propagation in presence rough surfaces, Rayleigh roughness criterion is a widely- used means to estimate degree considered surface. this paper, extended case layers. Thus, it provides an interesting qualitative tool for estimating

This paper describes the influence of oil pollution over sea surfaces on height spectrum and autocorrelation function rough surfaces. An slick damps capillarity waves surface reduces root mean square slope surface. These modified functions then have an radar cross section (RCS) from contaminated The bistatic RCS is presented by comparison with a clean sea: results benchmark numerical model are compared new semiempirical using geometric optics approximation first-order smallslope approximation.

An asymptotic method is described for predicting the bistatic normalized radar cross section of a rough homogeneous layer made up two surfaces. The model based on iteration Kirchhoff approximation to calculate fields scattered by layer, and reduced high-frequency limit in order obtain numerical results rapidly. Shadowing effects, significant large incidence or scattering angles, are taken into account through use shadowing functions. applicable moderate surface roughnesses having small...

The problem of hydrodynamic modeling the surfaces oil films at sea is treated by using physical models, namely, model local balance and Elfouhaily spectrum for describing clean surface. Then, this refined contaminated seas makes it possible to derive electromagnetic considering thin on Two simplifying approaches in dealing with complex double-layer are described, called "thin-layer" "classical" approaches. These two approaches, both having advantage reducing a single-layer problem, compared...

In civil engineering, conventional methods used to estimate the thickness of pavements assume flat interfaces. contrast, this study uses a rigorous electromagnetic method called propagation-inside-layer-expansion (PILE) simulate radar backscattered signal at nadir from rough pavement made up two interfaces separating homogeneous media. The statistical distribution first echoes is studied by comparison with default case, together their frequency behaviour. Within scope road survey ground...

In this article, the fields scattered by coated cylinders, a rough layer, and an object below surface are computed efficient propagation-inside-layer-expansion (PILE) method combined with physical optics (PO) approximation to accelerate calculation of local interactions on non-illuminated scatterer, which is assumed be perfectly conducting. The PILE based moments, impedance matrix two scatterers then inverted blocks from Taylor series expansion inverse Schur complement. Its main interest...

In the electromagnetic field, radar is widely used to measure or estimate media parameters detect targets through obstructions. For horizontally stratified media, layer thickness can be deduced from time delays of backscattered echoes and dielectric constants. The high-resolution method estimation signal via rotation invariance techniques (ESPRIT) has been proposed for time-delay estimation. practice with a radar, are correlated. order apply ESPRIT method, in this letter, we propose use two...

This paper is devoted to the forward radar propagation over clean and contaminated seas, using Ament model by taking shadowing effect into account. The well-known Rayleigh parameter, which characterizes degree of roughness a corrugated surface for case reflection on rough surface, presented. Then, it extended transmission through layer two interfaces. parameter allows then calculate oil slicks sea surfaces, model. Moreover, improved Numerical results seas are presented, compared that seas.

The objective of this paper is to develop innovative approaches obtain analytical expressions the radar cross section (RCS) perfectly conducting random rough surfaces under physical optics (PO) approximation. led take into account specific geometrical properties considered calculate their RCS. reduce computing time with respect numerical PO technique, which requires two integrations. All developed are validated by comparison a commercial code (the multilevel fast multi-pole method (MLFMM)...

This paper addresses the subject of electromagnetic wave scattering in layered media, thus covering recent progress achieved with different approaches. Existing theories and models are analyzed, classified, summarized on basis their characteristics. Emphasis is placed both theoretical practical application. Finally, patterns trends current literature identified critically discussed.

Scattering from very rough homogeneous layers is studied in the high-frequency limit (under geometric optics approximation) by taking shadowing effect into account. To do so, iterated Kirchhoff approximation, recently developed Pinel et al. [Waves Random Complex Media17, 283 (2007)] and reduced to used investigated more detail. The contributions higher orders of scattering inside layer are calculated under approximation. method can be applied either or perfectly flat lower interfaces,...

This article presents a new asymptotic modeling of electromagnetic (EM) wave coherent scattering from rough multilayered medium, based on the scalar Kirchhoff-tangent plane approximation. The proposed EM model is developed to simulate realistic ground-penetrating radar (GPR) signal that considers interface roughness multilayer. It allows us investigate influence amplitude GPR echoes coming medium. Sounded medium generally has low contrast between successive layers, so multiple reflections...

The statistical properties of the electromagnetic field backscattered from sea surfaces are studied by using asymptotic numerical methods. Sea modeled Elfouhaily et al. spectrum model. influence radar spatial resolution on statistics is for various wind conditions and configurations, considering equal range azimuth resolutions. It observed that phase can be assimilated to a uniform distribution amplitude resembles Rayleigh distribution. Moreover, reducing d induces stronger variability...

Horizontally stratified media are commonly used to represent naturally occurring and man-made structures, such as soils, roads, pavements, when probed by ground-penetrating radar (GPR). Electromagnetic (EM) wave scattering from multilayered is dependent on the roughness of interfaces. In this paper, we developed a closed-form asymptotic EM model considering random rough layers based scalar Kirchhoff-tangent plane approximation (SKA) that combined with planar Green's functions. order validate...

Abstract Many fast asymptotic models of electromagnetic scattering from a single rough interface have been developed over the last few years, but only on stacks interfaces. The specific case very surfaces, compared to incident wavelength, has not treated before, which is context this paper. model starts iteration Kirchhoff approximation calculate fields scattered by layer, and reduced high-frequency limit in order rapidly obtain numerical results. shadowing effect, important under grazing...

In civil engineering, ground penetrating radar is a common technique for evaluating the structure and quality of road pavement. This paper focuses on estimation time delay interface roughness engineering structure, like pavements. The influence taken into account in signal model. A modified parameters via rotational invariance (ESPRIT) algorithm combined with an interpolated spatial smoothing proposed. It allows us to jointly efficiently estimate by ultrawideband (the upper frequency up 8-10...

In the field of civil engineering, ground penetrating radar (GPR) is a highly efficient nondestructive testing tool for sustainable management pavement infrastructures. GPR allows to evaluate structure roadway over large distances (with contactless configurations) and detect significant subsurface defects. This letter presents new method thin debondings within structures with step-frequency GPR. The proposed enables us carry out detection only small number frequency samples A-scans. It based...

This paper studies the coherent scattering from random rough layers made up of two uncorrelated surfaces, by considering 2D problems. The results a rigorous electromagnetic method called PILE (propagation-inside-layer expansion) are used as reference. Also, asymptotic analytical approaches presented and compared to numerical model for comparison. cases surfaces with both Gaussian exponential correlations studied. approach is applied road survey GPR at nadir.

When solving scattering or emissivity problems for rough surfaces, the shadowing effect is often taken into account. Furthermore, surfaces with large root mean square slope, surface reflections of incidence emission ray should not be neglected, especially at observation angles. In this paper, a model monostatic statistical illumination function one-dimensional single reflection developed, which based on Smith function. A Monte Carlo ray-tracing algorithm used to evaluate accuracy present...

Surface reflection is an important phenomenon that must be taken into account when studying sea surface infrared emissivity, especially at large observation angles. This paper models analytically the polarized emissivity of one-dimensional surfaces with shadowing effect and one reflection, by assuming a Gaussian slope distribution. A Monte Carlo ray-tracing method employed as reference. It shown present model agrees well reference method. The calculated then compared measurements....