A hybrid 2-D ADI-FDTD subgridding scheme

Abstract

The finite-difference time-domain (FDTD) method gives accurate results but uses a large amount of computer memory and time, which can be reduced by applying higher resolution only around critical areas in the problem domain. In this paper, a new subgridding scheme have been proposed which based on the hybridization of the alterative-direction implicit FDTD (ADI-FDTD) and FDTD algorithms. The field components in fine local grids are updated using the ADI-FDTD method, and in the coarse main grids conventional FDTD method is utilized. The technique achieves the same time marching step in the whole domain as employed in the coarse FDTD scheme, and the need for the temporal interpolation of the fields in the fine grids is obviated since the ADI-FDTD scheme is unconditionally stable. Hence, the hybrid ADI-FDTD subgridding scheme is less time consuming and easy to implement. Practical applications of the algorithm in the simulations of the scattering of conducting cylinder and dielectric square cylinder are reported.