  We investigate the transport through a quantum ring, a dot and a barrier
embedded in a nanowire in a homogeneous perpendicular magnetic field. To be
able to treat scattering potentials of finite extent in magnetic field we use a
mixed momentum-coordinate representation to obtain an integral equation for the
multiband scattering matrix. For a large embedded quantum ring we are able to
obtain Aharanov-Bohm type of oscillations with superimposed narrow resonances
caused by interaction with quasi-bound states in the ring. We also employ
scattering matrix approach to calculate the conductance through a semi-extended
barrier or well in the wire. The numerical implementations we resort to in
order to describe the cases of weak and intermediate magnetic field allow us to
produce high resolution maps of the ``near field'' scattering wave functions,
which are used to shed light on the underlying scattering processes.
