This work numerically investigates a radiative flux management method via graphene-based metamaterial that exhibits tunable optical responses. The background spectrum tailoring, which can be considered as degeneration of Fabry-Perot resonance, has been investigated as the dominating factor to the radiation tuning. Two types of resonances, as surface plasmon polariton and phonon-mediated magnetic polariton, have been excited. The near field distributions have been studied to understand the physics for the resonances and background spectrum. Analytical modes, dispersion relationship for surface plasmon polariton and inductor-capacitor model for phonon-mediated magnetic polariton, have been utilized to verify the results. The fundamental understanding of graphene-associated background tuning gained herein will facilitate the design of thermally tunable metamaterial and broaden the basic understanding to broadband spectral tailoring. (C) 2016 Elsevier Ltd. All rights reserved.