Research On Analytical Model Of Electromagnetic Scattering From Randomly Rough Surfaces

The electromagnetic scattering theory of random rough surface plays an important role in microwave remote sensing.In the remote sensing of real surface such as land,the radar incident wave interacts with the surface in a complex way,and the scattering wave is generated in a random direction,which includes various surface information.According to the coefficient received by the radar,we can invert all kinds of parameters for environmental exploration,land and sea target detection and so on.It is of great theoretical significance to study the electromagnetic scattering characteristics of rough surfaces represented by land and sea surfaces.This paper mainly studies the analytical method of electromagnetic wave scattering of two-dimensional random rough surfaces.We introduce the classical scattering models such as kirchhoff approximation(KA),integral equation model(IEM)and improved integral equation model(AIEM)and extended improved integral equation model(EAIEM)based on IEM.For EAIEM model,a reflection coefficient transition model based on two local incident Angle approximation methods,rough surface parameters and incident wave property is proposed.For the rough surface of complex exponential spectral type,the band limited exponential power spectral density is introduced to solve the problem of non-derivation.The second order approximation of the error function is obtained by Taylor approximation,and for the cross term and the supplementary term obtained by the interaction of kirchhoff term and the supplementary term,some additional terms of the error function obtained by the second order approximation are added on the basis of the original analytic model.The model is divided into backscattering and double station scattering to verify the accuracy of the modified EAIEM model.The experimental results show that EAIEM Backscatter and Bistatic scattering both perform well.The accuracy of EAIEM model is improved without reducing the applicable range of EAIEM model.Especially when dealing with the high frequency and high scattering Angle problem of bistatic scattering.