A parameter optimized ADI-FDTD method based on the (2,4) stencil

This paper presents a parameter optimized alternating direction implicit (ADI) finite-difference time-domain (FDTD) method based on the (2,4) stencil (denoted as (2,4) parameter optimized (PO)-ADI-FDTD method) to achieve better dispersion performance. With different optimization schemes, the method can be applied to satisfy various requirements, such as zero numerical dispersion error (ZNDE) in the axes direction, ZNDE in the diagonal direction, zero anisotropy dispersion, ZNDE for two arbitrary angles, and minimum average dispersion error. Through the stability analysis for the (2,4) PO-ADI-FDTD method, it can be proved that all the schemes proposed here are unconditionally stable. The variation of the performance of the (2,4) PO-ADI-FDTD method for different frequencies is also studied. One can find that the desired performance of the (2,4) PO-ADI-FDTD method can be basically preserved within a frequency band without deterioration. Through comparison, it can be concluded that the (2,4) PO-ADI-FDTD method outperforms the previous parameter optimized ADI-FDTD method based on the (2,2) stencil in several aspects.