基于微面元理论的“猫眼”目标回波散射偏振特性研究

为了研究"猫眼"目标表面回波散射偏振特性,基于微面元理论建立了偏振双向反射分布函数模型,指出线偏振光在"猫眼"目标表面回波散射的偏振度与目标表面粗糙度、复折射率以及入射角、探测角有关。主要研究"猫眼"目标表面粗糙度对其回波散射偏振度的影响,利用Matlab仿真得到"猫眼"目标回波偏振度与目标表面粗糙度参数σ的关系曲线。选择经过不同砂纸打磨的硅片作为"猫眼"目标进行实验,当硅片表面均方根高度分别为0.067μm、0.554μm、0.726μm、1.651μm、1.893μm时,其表面回波散射偏振度的测量值依次为98.83%、98.16%、96.08%、94.91%、94.6%,表明"猫眼"目标回波散射的偏振度随其表面粗糙度的增大而减小。

Analysis of polarization characteristics for cat’s eye target echo scattering based on microfacet theory

In order to study the scattering polarization characteristics of cat's eye target echo, a polarized bidirectional reflection distribution function model was established based on the microfacet theory. The degree of polarization of the cat's eye target echo for linearly polarized light was related to target surface roughness, complex refractive index, incident angle and observation angle. The influence of the surface roughness of cat's eye target on the degree of polarization of its echo was studied. The relationship between the degree of polarization of cat's eye target echo and the target surface roughness parameter was obtained by Matlab simulation. The silicon wafers polished by different sandpapers were selected as the cat's eye target. When the root-mean-square heights of silicon wafers is 0.067 μm, 0.554 μm, 0.726 μm, 1.651 μm and 1.893 μm respectively, the degree of polarization of surface echo scattering is 98.83%, 98.16%, 96.08%, 94.91% and 94.6%, respectively. The degree of polarization of cat's eye target echo decreases with the increase of its surface roughness.