  Recent experiments have demonstrated that the metamaterial approach is
capable of drastic increase of the critical temperature Tc of epsilon near zero
(ENZ) metamaterial superconductors. For example, tripling of the critical
temperature has been observed in Al-Al2O3 ENZ core-shell metamaterials. Here,
we perform theoretical modelling of Tc increase in metamaterial superconductors
based on the Maxwell-Garnett approximation of their dielectric response
function. Good agreement is demonstrated between theoretical modelling and
experimental results in both aluminium and tin-based metamaterials. Taking
advantage of the demonstrated success of this model, the critical temperature
of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is
evaluated. The MgB2-based metamaterial superconductors are projected to reach
the liquid nitrogen temperature range. In the case of an H2S-based metamaterial
Tc appears to reach ~250K.
