Generation of Orbital Angular Momentum Vortex Beam Based on Reflectarray Antenna for Microwave Applications

A novel reflective unit cell is proposed to generate orbital angular momentum (OAM) based on reflectarray antenna. The designed unit cell nearly achieves 430° reflection phase at operating frequency. This range of phase shifts required to design a reflectarray antenna is obtained by adjusting length of a Screw-like element on one side of substrate. To obtain a linear phase response 3 mm air layer is considered between the dielectric and ground plane. Design and simulation process for both unit cell and full structure of antenna is done by CST Microwave Studio. Results show the proposed unit cell is a good candidate for wide-band OAM-reflectarray antenna and OAM vortex wave is generated effectively for two modes.