We propose a device based on an antidot embedded in a narrow quantum wire in
the edge state regime, that can be used to inject and/or to control spin
polarized current. The operational principle of the device is based on the
effect of resonant backscattering from one edge state into another through a
localized quasi-bound states, combined with the effect of Zeeman splitting of
the quasibound states in sufficiently high magnetic field. We outline the
device geometry, present detailed quantum-mechanical transport calculation and
suggest a possible scheme to test the device performance and functionality