A generalized eigenvalue method for fdtd analyses

In this article we apply the generalized eigenvalue method (GEM) to extract the complex exponentials from a truncated time record computed by the finite‐difference time‐domain (FDTD) code for analyzing microwave integrated circuits. To obtain accurate scattering parameters without further FDTD computations, the truncated FDTD time record is efficiently extended into the future by summing the complex exponentials with complex coefficients determined by the least‐squares method. Numerical GEM results with fewer poles are shown to be in good agreement with those obtained by the Prony method with a large number of poles.