▎ 摘　　要

A stability-improved auxiliary differential equation finite-difference time-domain (FDTD) method is developed for broadband modeling graphene-based devices in this letter. By introducing an electric polarization term characterized with an auxiliary equation, the graphene sheet is incorporated into the FDTD method without any decrease in theCourant-Friedrich-Levy number. The stability condition is analyzed and numerical experiments are carried out to validate the proposed method with analytical results. It is further applied to investigate some properties of metal-graphene split-ring resonator.