The wave-equation FD-TD method for the efficient eigenvalue analysis and S-matrix computation of waveguide structures

A modified finite-difference-time-domain (FDTD) formulation based on the direct discretization of the vector wave-equation is applied to the efficient analysis of hybrid-mode waveguiding structures. For both 3-D and 2-D waveguide eigenvalue problems, the formulation requires only one grid, and just the solution of three coupled equations is necessary. Numerical examples concerning the resonant frequencies for an inhomogeneously filled waveguide resonator as well as the fundamental- and higher-order-mode propagation factors for insulated image guides, shielded coupled dielectric guides, and lateral open dielectric ridge guides demonstrate the efficiency of the method. The theory is verified by comparison with results obtained by other methods