Fig. 1. Sketch of graphene-based metamaterial unit cell. ϵj and dj (j=1,2) are the relative dielectric permittivities and the thicknesses of the dielectric layers, respectively.

Fig. 2. Effective parameters (a) ϵx(eff) and (b) τ(eff) as functions of the graphene chemical potential μc.

Fig. 3. Comparison among the OTFs as evaluated from the exact matrix method (solid lines), from the standard EMT (dashed-circle lines), and from the nonlocal multiscale EMT (dashed lines). The functions MTF and PTF are related to the OTF by the relation OTF(kx)=MTF(kx) exp[iPTF(kx)] (i.e., MTF and PTF are the modulus and phase of OTF).