太赫兹低频段粗糙目标的表面散射及成像特性研究  

Surface Scattering and Imaging Characteristics of Rough Targets in Low-Frequency Terahertz Band

作　　者：柴鑫悦 胡浩 胡晓雪 马欣茹 席思星 王晓雷[1] Chai Xinyue;Hu Hao;Hu Xiaoxue;Ma Xinru;Xi Sixing;Wang Xiaolei(Institute of Modern Optics,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;School of Mathematics and Physics Science and Engineering,Hebei University of Engineering,Handan 056038,Hebei,China)

机构地区：[1]南开大学电子信息与光学工程学院现代光学研究所,天津300350 [2]河北工程大学数理科学与工程学院,河北邯郸056038

出　　处：《激光与光电子学进展》2024年第10期158-166,共9页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61875093)。

摘　　要：目标表面散射特性是利用太赫兹波进行雷达成像、目标识别和定位的物理基础,而影响目标表面散射特性的因素主要是目标材料和表面粗糙度。以金属铝材料为例,基于0.1 THz频点处的Drude模型参数拟合结果,利用基尔霍夫近似(KA)法分析了高斯型随机粗糙铝表面的散射系数。对蒙特卡罗(Monte-Carlo)粗糙目标的雷达散射截面(RCS)进行仿真分析,实现了二维逆合成孔径雷达(ISAR)成像。研究结果表明:目标RCS仿真结果与KA理论分析结果相符,即在小俯仰角下表面粗糙度与RCS呈负相关,而在大俯仰角下表面粗糙度与RCS呈正相关。此外,在一定的粗糙范围内,随着表面粗糙度的增加,目标表面的散射中心增多,在ISAR图像上形成密集的“斑点状”效果,更能反映目标的形状和结构。Target surface scattering characteristics are the physical basis of terahertz waves used in radar imaging and target recognition and location.The main factors affecting target surface scattering characteristics are the target material and surface roughness.This study uses metal aluminum as an example and fits the Drude model parameters of aluminum at O.1 THz.Based on the fitting results,the scattering coefficient of a Gaussian random rough aluminum surface is analyzed using Kirchhoff approximation(KA)method.Subsequently,Monte-Carlo rough targets with different roughness are modeled,and the radar scattering cross-section(RCS)is calculated to image the two-dimensional inverse synthetic aperture radar(ISAR).The research results show that the target RCS simulation results are consistent with KA theory analysis,that is,surface roughness is negatively correlated with RCS at a small pitch angle,whereas surface roughness is positively correlated with RCS at a large pitch angle.In addition,in a certain rough range,as the surface roughness increases,the scattering center of the target surface increases,and the ISAR image forms a dense"speckle"effect,which can better reflect the shape and structure of a target.

关 键 词：粗糙面散射 低频太赫兹波 散射系数 基尔霍夫近似 雷达散射截面 逆合成孔径雷达成像 

分 类 号：TN957.53[电子电信—信号与信息处理]