An FDTD-Based Method for Difference Scattering from a Target above a Randomly Rough Surface

The difference scattering field has been defined for studying the scattering from a target above a randomly rough surface, which is independent of the selection of rough surface's length theoretically. It is feasible to extend the conventional finite-difference time-domain (FDTD)-based method for calculating composite scattering field from the target/surface model to the calculation of the difference scattering field. However, the dependence of its solution on the choice of rough surface's length is significant, which is inconsistent with the intention of the proposal of difference scattering field. In this communication, a novel FDTD-based method is proposed for difference scattering calculation, which adopts different output boundary and incident wave introduction methods compared with the conventional method. The simulation results are given to verify that the proposed method can effectively reduce the dependence on the choice of the rough surface's length in the difference scattering calculation.