Envelope ADI-FDTD Method in 2D and 3D Domains

Abstract — The numerical performance of the envelope ADI-FDTD method was studied in this paper. The ADI-FDTD method is independent of the Courant-Friedrich-Levy (CFL) stability condition, but its numerical dispersion grows with the increase of the time-step size. By introducing the envelope technique in the ADI-FDTD method, the numerical accuracy can be improved efficiently. In this paper, the numerical phase velocity of the envelope ADI-FDTD method was discussed. A 3-D cavity problem was also simulated for the envelope ADI-FDTD, ADI-FDTD, and the conventional FDTD methods. The simulation results show the superior performance of the envelope ADI-FDTD over the ADI-FDTD in numerical accuracy. Key Words — ADI-FDTD method, envelope ADI-FDTD method, CFL stability condition, waveguide problem, cavity problem. I