Implementation of 3D ID-FDTD scheme for lossless media

This paper implements the 3D isotropic dispersion (ID) FDTD with modified UPML and TF/SF boundary. To efficiently calculate the optimal weighting factor, an equation is formulated by using polynomial curve-fitting. From stability analysis, the 3D ID-FDTD extends the maximum time step by about 35% more than the standard FDTD, reducing the additional computation time due to increased complexity of the 3D ID-FDTD scheme. When applied to a scattering problem of a dielectric sphere, the ID-FDTD scheme generates more accurate results than that of the standard scheme, especially in the forward direction.