  We study the paradigmatic model of a qubit interacting with a structured
environment and driven by an external field by means of a microscopic and a
phenomenological model. The validity of the so-called fixed-dissipator (FD)
assumption, where the dissipation is taken as the one of the undriven qubit is
discussed. In the limit of a flat spectrum, the FD model and the microscopic
one remarkably practically coincide. For a structured reservoir, we show in the
secular limit that steady states can be different from those determined from
the FD model, opening the possibility for exploiting reservoir engineering. We
explore it as a function of the control field parameters, of the
characteristics of the spectral density and of the environment temperature. The
observed widening of the family of target states by reservoir engineering
suggests new possibilities in quantum control protocols.
