The rigorous second-order accurate FDTD equations at dielectric interfaces are derived through the discretization of the integral forms of Maxwell′s curl equations on the non-uniform Yee′s lattice and Taylor serious expending of continuous field components over finite volumes including the interfaces.

For the study of the computational domain filled with different dielectric materials and the reasonable division of coarse and fine grids in different dielectric regions,the second-order accurate FDTD technique at the dielectric interface is employed to analyze the tangential electric field components at the interface.