  A detailed description of the tunneling processes within Aharonov-Bohm (AB)
rings containing two-dimensional quantum dots is presented. We show that the
electronic propagation through the interferometer is controlled by the spectral
properties of the embedded dots and by their coupling with the ring. The
transmittance of the interferometer is computed by the Landauer-B\"uttiker
formula. Numerical results are presented for an AB interferometer containing
two coupled dots. The charging diagrams for a double-dot interferometer and the
Aharonov Bohm oscillations are obtained, in agreement with the recent
experimental results of Holleitner {\it et al}. [Phys. Rev. Lett. {\bf 87},
256802 (2001)] We identify conditions in which the system shows Fano line
shapes. The direction of the asymetric tail depends on the capacitive coupling
and on the magnetic field. We discuss our results in connection with the
experiments of Kobayashi {\it et al} [Phys. Rev. Lett. {\bf 88}, 256806 (2002)]
in the case of a single dot.
