A Fast Method for Transient Electromagnetic Scattering from a Ship on Rough Sea Surface

An efficient time-domain hybrid method combining time-domain integral equation (TDIE) and time-domain Kirchhoff approximation (TDKA) is proposed to calculate transient electromagnetic (EM) scattering of a 2D ship floating on a randomly rough sea surface under TM pulse wave incidence. In this hybrid method, the composite scattering model is divided into TDIE region and TDKA region. The TDIE region includes the ship and its adjacent sea surface, whereas the rest of the sea surface is designated as the TDKA region. The induced electric currents in the TDIE region and TDKA region are solved by TDIE and TDKA methods, respectively. To consider the coupling interactions between the TDIE region and the TDKA one, an iterative marching-on-in-time (MOT) based formulas are given and used to solve the transient scattering from a 2D ship on a sea surface. The accuracy and performance of the presented hybrid method are validated by comparing the backward scattered and specular scattered electric fields with those calculated by the full TDIE method. Numerical results show that the hybrid method of TDIE-TDKA can greatly reduce computational time with good calculation accuracy.