▎ 摘　　要

Light absorption is essential in the construction of photodetectors and photovoltaic applications. In this work, the absorption properties of a defective photonic crystal are analyzed in the GHz region using the transfer matrix method. The defect layer is assumed to be a metamaterial of negative optical parameters sandwiched between two sheets of graphene. The tunable properties of absorption are investigated with the graphene chemical potential and phenomenological scattering rate and the thickness of the metamaterial layer. The results reveal that the number, position and height of the absorption resonant peaks are tuned by graphene optical properties. The spectra are studied with and without graphene sheets and an extra peak is created when two sheets of graphene are inserted on both sides of the metamaterial. The proposed photonic device can be useful in designing graphene and metamaterial-based optical devices such as absorbers, filters and sensors in the GHz region.