  We consider a magnetic Schroedinger operator in a planar infinite strip with
frequently and non-periodically alternating Dirichlet and Robin boundary
conditions. Assuming that the homogenized boundary condition is the Dirichlet
or the Robin one, we establish the uniform resolvent convergence in various
operator norms and we prove the estimates for the rates of convergence. It is
shown that these estimates can be improved by using special boundary
correctors. In the case of periodic alternation, pure Laplacian, and the
homogenized Robin boundary condition, we construct two-terms asymptotics for
the first band functions, as well as the complete asymptotics expansion (up to
an exponentially small term) for the bottom of the band spectrum.
