Size Effects in Periodic Metamaterials

The optical properties of periodic electromagnetic metamaterials are considered as functions of their relative unit cell size $d / \lambda$. The reflection $R$ and transmission $T$ coefficients are numerically calculated for some realistic metamaterials in a wide range of their relative unit cell size values that comprises different operating regimes of the metamaterials. Peculiarities in $R$ and $T$ behavior are discussed and the causes of those peculiarities are outlined. The obtained results support the opinion on inapplicability of the very homogenization concept to metamaterials whose unit cell size is comparable to the incident wavelength, in contrast to some previously published results.