A Subgrid Model Utilizing Extra- and Inter-polation Schemes for the Nonstandard FDTD Method

The use subgridding in the finite-difference time-domain (FDTD) method can significantly reduce the overall computational burden. This is particularly applicable in the scattering analysis of electrically-large objects with partially fine structures or dielectrics, such as aircrafts or ships. In this paper, we propose a 3D subgrid model for the nonstandard (NS) FDTD method via simple extra- and inter-polation schemes for efficient grid connection. Also, a perfectly matched absorber is employed to mitigate long-time instabilities. Numerical results verify that the proposed model exhibits high accuracy even in its simple form; it has sufficient stability and low system costs.