二维粗糙面两束波束散射特性研究

基于Kirchhoff近似,推导两束波束散射强度相关系数的表达式,数值计算漫射强度及散射强度相关系数随角度差、相关长度及粗糙度变化情况。结果表明:散射角对粗糙表面相干散射强度与光滑表面相干散射强度的比值有影响,当两束波束的入射角、方位角均相等,意味着两束波束相互重合且散射强度比值为单波束比值的四倍;当两束波束的入射角、方位角中有一个角度不相等,由散射场干扰效应的影响,相干散射强度比值都会减小。相关长度的变化与漫射强度和散射强度相关系数均成正比;随着入射角度差增大,漫射强度的后向散射效应增强,且散射强度相关系数变小,说明两束波束的干扰越严重;随着散射角的增大,总散射强度受干扰项散射强度影响较大,则后向散射效应增强。

Study on two-beam beam scattering characteristics of two-dimensional rough surface

Based on Kirchhoff approximation,the expression of correlation coefficient of scattering intensity of two beams is derived,and the variation of diffusion intensity and scattering intensity correlation coefficient with angle difference,correlation length and roughness is numerically calculated. The results show that the scattering angle has an effect on the ratio of coherent scattering intensity of rough surface to that of smooth surface. When the incident angle and the azimuth angle of the two beams are equal,it means that the two beams coincide with each other and the scattering intensity ratio is four times the ratio of single beam;when one of the angles of incidence and azimuth of the two beams is not equal,the coherent scattering intensity ratio will decrease due to the interference effect of scattering field;the change of correlation length is proportional to the diffusion intensity and the correlation coefficient of scattering intensity. As the incident angle difference increases,the backscattering effect of the diffuse intensity increases,and the scattering intensity correlation coefficient becomes smaller,indicating that the interference of the two beams is more serious;as the scattering angle increases,the total scattering intensity is greatly affected by the scattering intensity of the interference term,and the backscattering effect is enhanced.