the time step length of traditional equal-time-step non-uniform finite-difference time-domain (ETS-FDTD) method is determined by the minimized grid size
which results in a long computational time.A multi-time-step finite-difference time-domain (MTS-FDTD) method is presented
which uses different time step lengths in different grid regions to reduce computational time.Numerical results demonstrate that MTS-FDTD method reduces more than 42 percent of computational time than ETS-FDTD method.