High-Frequency Method for Scattering from Coated Targets with Extremely Electrically Large Size in Terahertz Band

This article presents a high-frequency method for the prediction of radar cross-section of coated targets with extremely electrically large size in the terahertz band in free space. To consider the scattering characteristics of the coated targets with a rough surface in the terahertz band, taking into account the effect of surface roughness, the reflection coefficients on the smooth coating surface can be modified; the equivalent electric and magnetic currents on the surface can then be corrected by the modified reflection coefficients to obtain the electric and magnetic induced current densities on the rough coating surface. Therefore the physical optics method, which was combined with the graphical electromagnetic computing method and improved using the partition display algorithm, can be used to solve the scattered fields, and the radar cross-section of the coated targets with a rough surface in the terahertz band can then be obtained. Numerical results for several coated targets, such as the mother warhead of the Minuteman III intercontinental ballistic missile and VFY-218 aircraft, are given and discussed. The results provide an important basis and method for applications of terahertz radar in many fields, such as military, astronomy, and remote sensing, in the future.