Abstract
We investigate the quantum size effect in the phase coherent mesoscopic ring. A quantum dot is embedded in one arm and it is connected to one lead via tunnel barrier. Both Aharonov-Casher and Aharonov-Bohm effects are studied. A spin-dependent conductance has been deduced and it depends on the intrinsic parameters. Our results show that the strength of spin-orbit coupling depends on the size of the present device. This investigation is valuable for fabricating such spintronics devices.