Corrected impulse invariance method for dispersive media using FDTD

Electromagnetic wave propagation in dispersive media can be modeled conveniently using the finite-difference time-domain (FDTD) method in conjunction with the impulse invariance method of Z-transform theory. However, the classical impulse invariance method has been found to be incorrect and inaccurate when the impulse response is discontinuous at the initial time t = 0 . A corrected impulse invariance method is employed in this paper to develop the FDTD update equations for modeling dispersive media. Numerical results show that improved accuracy can be achieved through the corrected impulse invariance method compared to the classical impulse invariance method.