  We study the localization transitions for coupled one-dimensional lattices
with quasiperiodic potential. Besides the localized and extended phases there
is an intermediate mixed phase which can be easily explained decoupling the
system so as to deal with effective uncoupled Aubry-Andr\'e chains with
different transition points. We clarify, therefore, the origin of such an
intermediate phase finding the conditions for getting a uniquely defined
mobility edge for such coupled systems. Finally we consider many coupled chains
with an energy shift which compose an extension of the Aubry-Andr\'e model in
two dimensions. We study the localization behavior in this case comparing the
results with those obtained for a truly aperiodic two-dimensional (2D)
Aubry-Andr\'e model, with quasiperiodic potentials in any directions, and for
the 2D Anderson model.
