An Enhanced Stability Subgrid Scheme for the Nonstandard-FDTD Technique

In the scattering analysis, via the FDTD method, of electrically large objects with partially fine structures, the subgrid model is an instructive approach for the reduction of the system overhead. Such a concept has been lately presented for the non-standard (NS) FDTD algorithm; yet with potential instabilities for prolonged simulations. To address this issue, a new FD connection method, incorporating multiple Gaussian smoothing at the cell boundaries, is introduced. Compared with the existing model, results reveal a notable stability enhancement of more than tenfold with an artificial loss for stabilization of 1/10. So, the superior stability and memory reduction ability of the featured formulation is validated and accordingly extended.