A domain decomposition FDTD method for scattering from very large rough surfaces

The FDTD method has been previously used to investigate the problem of scattering from rough surfaces, with sizes whose maximum area was 51.2λ × 51.2λ at 0.3 GHz. Domain decomposition (DD) methods have been proposed in the past to improve the computational efficiency of techniques dealing with large scatterers or with a complex structure. In this work, a DD-FDTD method is proposed to simulate the scattering phenomenon from very large rough surfaces. The size of the subdomains can be chosen to be within the memory limit. The coupling between adjacent subdomains is evaluated to account for mutual interaction effects between the subdomains by using a reaction integral based on the reciprocity theorem.