This paper proposes, an annular slot antenna with inner feeding network to generate Orbital Angular Momentum (OAM) waves at 5.4 GHz frequency, for WLAN application. The proposed OAM antenna system is smaller in size because open-ended microstrip lines are used as radiator along with annular slotted ground plane. Parametric variation and far field radiation patterns are presented and discussed. 3D phase patterns proves the generation of OAM waves of different OAM modes using proposed OAM antenna. © 2020 IEEE.