Analysis of Far-Field Scattering and Near-Field Coupling of a Target above Rough Surface Using DD-FDTD

A domain decomposition-finite difference time domain (DD-FDTD) method analyzing the far-field scattering and near-field coupling of a target above the rough surface is presented to reduce the computational burden. The domain decomposition scheme is introduced to place the target and the rough surface into two FDTD domains referred to as the target subdomain and the rough surface subdomain. The field continuity of the target subdomain is ensured by injecting the reflected wave from the rough surface into it. The reflected wave is computed by running the finite difference time domain (FDTD) in the rough surface subdomain and by transforming the near field according the Green's function. As a result, a large number of meshes between target and rough surface is removed, so the computational burden is reduced in the FDTD method. The numerical results compared with the conventional FDTD method show that the DD-FDTD is more efficient, especially when the distance between the target and rough surface becomes larger.