Conformal finite-different time-domain (FDTD) with overlapping grids

It is shown how to use many overlapping conformal grids in the neighborhood of the scatterer while using a rectangular grid away from the scatterer for solving Maxwell´s equations. The locally conformal grids allow better approximation of the boundary condition on the scattering object while the rectangular grid preserves the simplicity and accuracy of the regular finite-difference time-domain (FDTD) algorithm. These grids overlap typically about three zones. It is shown how to connect together the calculations done in different overlapping grids