In this paper, the potential of graphene in the design of reconfigurable nanoantennas is investigated based on the characteristic modes analysis approach. The characteristic modes (CMs) of a graphene plate are calculated by the electrical field integral equation technique. The effects of the dimensions and chemical potential of the graphene plate on the CMs are investigated. For achieving CMs, a novel formulation is introduced. The results of this analysis can be useful in designing efficient nanoantennas for wireless communications in the terahertz band.