Spatially-filtered FDTD subgridding for ground penetrating radar numerical modeling

Subgridding schemes are often implemented in the standard finite-difference time-domain (FDTD) method especially when fine geometric features and/or media with a high relative permittivity need to be modeled. In this paper, we propose an FDTD subgridding scheme which employs spatial filtering, to numerically model ground penetrating radar (GPR), using time steps well beyond the FDTD stability limit. To demonstrate the accuracy and efficiency of the proposed approach, comparisons of its numerical modeling results with the standard FDTD method and a previously proposed subgridding scheme are provided.