Stability preserving model order reduction of FDTD with stability enforcement beyond the CFL limit

Timestep in the Finite Difference Time Domain method (FDTD) is constrained by the Courant-Friedrichs-Lewy (CFL) limit. Several methods have been proposed to break the CFL barrier, including implicit formulations, spatial filtering, and projection of FDTD equations onto a stable subspace. In this work we present a novel approach based on model order reduction of FDTD equations. Compared to existing techniques, the new method has higher computational efficiency, guarantees stability below and above the CFL limit, and preserves the structure of FDTD equations.