Electromagnetic waves through metamaterial superlattices

We present new results of the transmission coefficients and phase times of metamaterial superlattices, built of alternating layers of left and right handed materials. We show that for certain relations of the metamaterial-superlattice parameters, the bands of the transmission coefficients become a sequence of isolated and equidistant peaks with negative phase times. We show also that the space-time evolution of a Gaussian wave packet, with centroid at any of these peaks, agrees with the theoretical predictions and no violation of the causality principle occurs.