Study On Electromagnetic Scattering From Rough Surface Based On BRDF

Bidirectional Reflectance Distribution Function could describe the scattering andradiation characteristics from rough surface and have important applications in the fieldof target detection, tracking, recognition, feature extraction and stealth technology.Using Bidirectional Reflectance Distribution Function to study the properties ofrandomly rough surface scattering is proposed in this paper. A method to calculatespatial bidirectional reflectance distribution function characteristics of randomly roughsurface is presented.First, the statistical properties parameters of rough surface are introduced, andbackscattering cross sections of two-dimensional rough surfaces are disscussed usingthe small perturbation method and the Kirchhoff approximation at different roughnessand different polarization state; The basic principles of the finite element method isdisscussed and the weak formulation of Galerkin method is derived in thetwo-dimensional practical problems, and the effect of different rms height andcorrelation length on rough surfaces are disscussed; Using the finite element method,the scattering intensity and the incident intensity can be obtained from the calculation ofthe unit solid angle, and then the BRDF is obtained. The agreement of the resultscompared with the Method of Moment (MoM) verifies that this method could calculatethe electromagnetic scattering field efficiently and straightforwardly; BRDF of differentrough surfaces are calculated, and the scattering characteristics of an electrically largerough surface can be substituted by combination of subsection electromagnetic field.The resulting combined fields from subsections of the rough surface show a good matchwith the entire scattering field of a whole surface. On the basis, the oblique incidentcase is discussed to prove that this method is also applicable.