Efficient generation of FDTD subcells using Krylov subspace technique to the wave equation

This letter describes an efficient method for generating finite difference time domain (FDTD) subcells directly from the wave equation. An efficient macromodel technique is employed to reduce the number of internal state variables for a region functioning as a subeell in the FDTD method. Using a system of second-order state space equations to generate macromodels for objects with fine structural details, the macromodels are constructed with fewer internal state variables. The proposed method is tested against a couple of scattering examples to show the accuracy and efficiency.