Terahertz Scattering Characteristics of Rough Metallic and Dielectric Corner Reflectors

Abstract

In this paper, scattering characteristics of rough metal and dielectric corner reflectors in THz band is analyzed. As a typical target, the research on scattering characteristics of corner reflector, which includes specular scattering, non-specular scattering and multi-path scattering in THz band, is of great significance for THz radar target detection and recognition. In terahertz low frequency band, metal targets can be regarded as a perfect electric conductor (PEC) with random small rough surfaces, which only needs to solve its induced electric current. However, for dielectric target, both the induced electric and magnetic current should be considered. Based on physical optics approximation and principal value integral form of the surface integral equation, iterative physical optics (IPO) method is used to calculate multiple scattering fields of dielectric target. The Gaussian rough surface profile satisfying Kirchhoff approximation is simulated by the linear filtering method. The total scattering field is obtained by the coherent superposition of each facet via the electromagnetic current radiation integral equation in the far field approximation. The scattering characteristics of rough metal and rough dielectric corner reflectors in THz band are numerically calculated. The influence of roughness and material on the scattering characteristics is analyzed, and it can be degenerated into a simple form of smooth PEC target. The results show a degradation of back RCS attributed to diffuse reflection for corner reflectors with rough surface compared to the smooth surface for both HH and VV polarizations. The roughness effect and dielectric parameters on scattering characteristics of Rough Metallic and Dielectric Corner Reflectors in Terahertz band provides a theoretical basis for the analysis of THz scattering and target detection.