粗糙金属和介质目标的太赫兹散射特性分析  

The Terahertz Scattering Analysis of Rough Metallic and Dielectric Targets

作　　者：牟媛 吴振森 赵豪 武光玲 Mou Yuan;Wu Zhensen;Zhao Hao;Wu Guangling(School of Physics and Optoelectronic Engineering, Xidian University, Xi＇an 710071, China;School of Electronic Engineering, Xidian University, Xi＇an 710071, China)

机构地区：[1]西安电子科技大学物理与光电工程学院,西安710071 [2]西安电子科技大学电子工程学院,西安710071

出　　处：《雷达学报（中英文）》2018年第1期83-90,共8页Journal of Radars

基　　金：国家自然科学基金(61571355)~~

摘　　要：太赫兹频段金属和介质粗糙目标的散射特性是研究太赫兹雷达目标特性的重要基础。当目标表面的主曲率半径远远大于入射波长,且粗糙表面高度起伏与斜率起伏远小于入射波长时,根据稳定相位法和标量近似法,可获得粗糙金属和介质目标的相干散射截面和非相干散射截面。基于稳定相位法,任意目标的相干散射截面可退化为粗糙导体、光滑介质和粗糙介质目标的相干散射。该文分析了电大尺寸光滑金属铝和介质白漆球的散射截面,与Mie理论计算的介质球的散射特性吻合,散射截面误差小于0.1 d Bm^2。采用朗伯定理,验证了粗糙介质球的太赫兹非相干散射精确解,当目标表面剖分精度越高,非相干散射的计算精度越高。该文数值计算了粗糙介质球的太赫兹相干和非相干散射特性,分析了表面粗糙度和表面材料对散射特性的影响,为电大尺寸空间目标太赫兹散射特性分析提供了理论基础。The terahertz scattering characteristics of metallic and dielectric rough targets is important for the investigation of the terahertz radar targets properties. According to the stationary phase theory and scalar approximation, if the radius of curvature at any point of the surface is much larger than the incident wavelength, and the wavelength is also much longer than the surface height function and Root-Mean-Square（RMS） surface slope, the coherent and incoherent scattering Radar Cross Section（RCS） of rough metallic and dielectric targets can be obtained. Based on the stationary phase approximation, the coherent RCS of rough conductors, smooth dielectric targets and rough dielectric targets can be easily deputed. The scattering characteristics of electrically large smooth Al and painted spheres are investigated in this paper, and the calculated RCS are verified by Mie scattering theory, the error is less than 0.1 d Bm^2. Based on lambert theory,it is demonstrated that the incoherent RCS is analyzed with better precision if the rough surfaces are divided into much more facets. In this paper, the coherent and incoherent scattering of rough Al and painted spheres are numerically observed, and the effects of surface roughness and materials are analyzed. The conclusions provide theoretical foundation for the terahertz scattering characteristics of electrically large rough targets.

关 键 词：太赫兹 相干散射 非相干散射 电大尺寸 

分 类 号：O436.2[机械工程—光学工程]