  We present a phenomenologically motivated model which is able to give rise
both to an inflationary epoch and to the present day cosmic acceleration. We
introduce an approach where the energy density depends on the scale factor $a$
in such a way that a smooth transition from the inflation to the matter
dominated era and then to the nowadays accelerated expansion is achieved. We
use the dimensionless coordinate distance $y(z)$ to the Gold Type Ia Supernovae
dataset and to a sample comprising 20 radio galaxies, the shift parameter
${\cal{R}}$ and the acoustic peak parameter ${\cal{A}}$ to test whether the
model is in agreement with observations and to constrain its main parameters.
As an independent cross check, we also compare model predictions with the
lookback time to galaxy clusters and the age of the universe. Although
phenomenologically inspired, the model may be theoretically motivated either
resorting to a scenario with a scalar and phantom fields (eventually
interacting) or as an effective description arising from higher order gravity
theories.
