Time Domain Parabolic Equation Method for Scattering Analysis of Electrically Large Coated Objects by using Impedance Boundary Condition

The time domain parabolic equation method (TDPE) is an efficient tool for analyzing electromagnetic (EM) scattering by electrically large objects. It reduces the cost of computational resources by dividing three-dimensional solution space into multiple twodimensional transverse planes for calculating scattered fields one by one. For thin coated perfectly electrically conducting (PEC) objects, the efficiency of TDPE method will decrease if dielectric is considered to be meshed. As an approximate method, Leontovich impedance boundary condition (IBC) handles this problem by modeling a surface impedance on the outer surface of coating dielectric, instead of solving Maxwell's equations in the dielectric domain. Thus in this paper, TDPE method based on Leontovich IBC is proposed to analyze broadband scattering problems of large-scale coated PEC objects. Numerical results have validated the accuracy and efficiency of the proposed method.