  The electronic transport in a system of two quantum rings side-coupled to a
quantum wire is studied via a single-band tunneling tight-binding Hamiltonian.
We derived analytical expressions for the conductance and spin polarization
when the rings are threaded by magnetic fluxes with Rashba spin-orbit
interaction. We show that by using the Fano and Dicke effects this system can
be used as an efficient spin-filter even for small spin orbit interaction and
small values of magnetic flux. We compare the spin-dependent polarization of
this design and the polarization obtained with one ring side coupled to a
quantum ring. As a main result, we find better spin polarization capabilities
as compared to the one ring design
