According to the characteristics of the polarizability in frequency domain of three commonmodels of dispersive media, the relation\nbetween the polarization vector and electric field intensity is converted into a time domain differential equation of second order\nwith the polarization vector by using the conversion from frequency to time domain. Newmark ???????? difference method is employed\nto solve this equation. The electric field intensity to polarizability recursion is derived, and the electric flux to electric field intensity\nrecursion is obtained by constitutive relation. Then FDTD iterative computation in time domain of electric and magnetic field\ncomponents in dispersive medium is completed. By analyzing the solution stability of the above differential equation using central\ndifference method, it is proved that this method has more advantages in the selection of time step. Theoretical analyses and\nnumerical results demonstrate that this method is a general algorithm and it has advantages of higher accuracy and stability over\nthe algorithms based on central difference method.
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