  Experimental realization of efficient graphene-based absorbers is a
challenging task due to the low carrier mobility in processed graphene. In this
paper, we circumvent this problem by placing uniform graphene sheets on
metallic metasurfaces designed for improving the absorption properties of
low-mobility graphene. Complete absorption can be achieved for different
frequencies with the proper metasurface design. In the THz band, we observe
strong tunability of the absorption frequencies and magnitudes when modulating
graphene Fermi level.
