Abstract: Considering the scattering analysis complexity of plasma over a broad frequency band, a new frequency-sweep analysis method is proposed based on the best uniform approximation theory. In the proposed algorithm, the Chebyshev series are used to approximate the surface current, which is marched to be a rational function by Maehly method to improve the accuracy greatly. Compared with the traditional Taylor-Padé model in asymptotic waveform evaluation (AWE) technique, it can accomplish the scattering analysis accurately over a broader frequency band with lower memory consumption, especially for the frequency-sweep analysis of plasma which is usually a dispersive dielectric object, the proposed method can avoid complex computation of high order derivates for impedance matrix elements. Different numerical examples are discussed, and it is shown that the proposed method can be used as an efficient tool to analyze scattering characters of plasma over a broad frequency band.