摘要： Graphene is a promising carbon nanomaterial, and multilayer graphene are more interesting than the monolayer one. The dispersion of multilayer graphene at terahertz (THz) leads to difficulties in transient electromagnetic simulation, e.g. the time domain integral equation (TDIE) method. This paper aims to achieve accurate fitting of multilayer graphene dispersive surface conductivity/impedance over ultra wideband THz frequencies. Graphene surface conductivity/impedance at THz is calculated by the Kubo formula. Thereafter, the surface conductivity and impedance is approximated by vector fitting method with expansions of several pairs of poles and residues. Numerical results are provided to validate the proposed method. Multilayer graphene time domain surface impedance which is used in the impedance boundary condition (IBC) for TDIE can be obtained readily by the inverse Fourier transform of its frequency domain counterpart.