A finite-different time-domain subgrid algorithm locally refines the mesh at regions requiring higher resolution. A novel separation of spatial and temporal subgridding interfaces is presented that allows implementing a novel spatial subgridding method and investigating the stability of each subalgorithm individually. Details are given for a spatial subgridding algorithm having a 1:3 mesh ratio. In the spatial subgridding algorithm, the fine-mesh is constructed with a recessed interface and the interpolation scheme is designed to be symmetric to maintain the stability of the update process. The stability of the spatial subgridding algorithm is analyzed with a matrix method. Numerical examples showing stability and accuracy are provided.


Electrical and Computer Engineering

Second Department

Materials Science and Engineering

Keywords and Phrases

Electromagnetic Wave Scattering; Finite Difference Time-Domain Analysis; Finite-Difference Time-Domain (FDTD); Finite-Different Time-Domain Subgrid Algorithm; Matrix Algebra; Matrix Method; Spatial Interfaces; Spatial Subgridding; Stability; Stability Analysis; Subgrid; Temporal Interfaces

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2007 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.