Numerical dispersion of precise integration time domain method in lossy media

In this paper, both numerical loss and numerical dispersion in precise integration time domain (PITD) method are investigated.It is shown that numerical loss in PITD method is always larger than the physical value, and numerical phase velocity in PITD method can be larger than the physical value.Both numerical loss and numerical dispersion in PITD method can be made nearly independent of time step size.The smaller spatial step size always gives smaller numerical loss error and smaller numerical dispersion error in PITD method.With smaller electric conductivity, both numerical loss error and numerical dispersion error in PITD method are larger than those in finite difference time domain (FDTD) method.With larger electric conductivity, numerical phase velocity in PITD method is closer to the physical phase velocity as compared with FDTD method.The anisotropies of PITD method in 3D case are usually larger than those in 2D case.The numerical results show that for good conductors, PITD method gives better accuracy and is more efficient in execution time than FDTD method.