Fast FDTD Simulation of Waveguide Components by the Matched Modal Source Method

In this work a Matched Modal Source Boundary Condition (MMSBC) is proposed for the fast FDTD simulation of waveguide components. The MMSBC allow the generation of a given incident wave while absorbing each modal component reflected from a discontinuity. It is shown that the scattering parameters of a waveguide structure can be computed accurately by incorporating the MMSBC algorithm into the FDTD simulator. This approach is numerically very efficient since it reduces the FDTD computational domain to the smallest volume allowed by the structure.