  The electronic transport of a noninteracting quantum ring side-coupled to a
quantum wire is studied via a single-band tunneling tight-binding Hamiltonian.
We found that the system develops an oscillating band with antiresonances and
resonances arising from the hybridization of the quasibound levels of the ring
and the coupling to the quantum wire. The positions of the antiresonances
correspond exactly to the electronic spectrum of the isolated ring. Moreover,
for a uniform quantum ring the conductance and the persistent current density
were found to exhibit a particular odd-even parity related with the ring-order.
The effects of an in-plane electric field was also studied. This field shifts
the electronic spectrum and damps the amplitude of the persistent current
density. These features may be used to control externally the energy spectra
and the amplitude of the persistent current.
