A hybrid implicit-explicit FDTD scheme with weakly conditional stability

Abstract

A hybrid implicit-explicit FDTD (HIE-FDTD) algorithm is proposed in this paper. In the HIE-FDTD algorithm, semi-implicit- and explicit-difference schemes are imposed on two different field components, respectively, and the field component with implicit difference is updated by solving simple tridiagonal matrix equations. The HIE-FDTD method, although conditionally stable, allows for larger time-step size than the conventional FDTD method because the stability condition of the HIE-FDTD method is weaker than that of the conventional Yee's FDTD algorithm. The demonstrated numerical dispersion relation of the HIE-FDTD method is found to be identical to that of the ADI-FDTD method. The accuracy and efficiency of the HIE-FDTD are verified by numerical simulation results.