Effects of rough surface scattering on terahertz radar imaging

Traditional millimeter wave security imaging radar ignores the effects of scattering due to the point target assumption. However, for frequencies in the terahertz band, the target surface should be modeled as a rough surface and the effects of scattering must be considered. In this paper, a small perturbation method (SPM) is used to get the backscattering coefficient of a rough surface. Then, the imaging results for the traditional security radar imaging model are simulated for various roughnesses. The effects of key scattering parameters including the roughness and frequency are then analyzed by comparisons with a Lambert surface and an ideal specular surface. The results show that a greater backscattering persistence angle improves the imaging quality with terahertz security radar imaging. The results also show that the angular width and shape of the backscattering characteristic curve both affect the imaging resolution and peak side lobe ratio. Finally, increasing the electromagnetic wave frequency facilitates rough surface imaging. © 2019, Tsinghua University Press. All right reserved.