A Simple High-Accuracy Subgridding Scheme

This paper introduces a novel method of embedding areas with a denser mesh into the FDTD (Finite Difference Time Domain) algorithm. A simple linear interpolation of electric and magnetic fields is used to link fine and coarse meshes. The method requires the refinement factor to be an odd integer and gives ultra-low reflections from subgridded areas thus highly increasing accuracy of the FDTD computation while simultaneously reducing the computation time. Tests are presented showing significant improvement in reflection from the coarse-fine mesh boundary over almost all methods published so far, without complicated and time consuming interpolations.