  The evolution of two coupled mini-bands, generated by alternating barrier
widths dimerization of a superlattice, driven by intense AC fields is
investigated. The present model delivers a useful framework for the transition
between the analytical high frequency regime and the extreme low frequency
limit described by models based on Fukuyama's {\it et al.} (Phys. Rev. B {\bf
8}, 5579 (1973)) proposal.
