Microstrip Reflectarray for Generation of Electromagnetic Waves with Beam Vorticity.

One type of orbital angular momentum (OAM) reflectarray antenna is presented to radiate the electromagnetic wave with beam vorticity. Microstrip double square loops are adopted as the element for the proposed reflectarray. Reflect phase of the elements with various sizes are analyzed by HFSS software with periodic boundary condition and Floquet mode. Then massive elements with different sizes are arranged helically to form the reflectarray, transforming the incident spherical wave into a vortex phase front. Several OAM reflectarray examples with different OAM mode and different feed mode are designed and fabricated. The phase patterns of far-zone field are simulated by FEKO software and measured by near-field scanning system, which demonstrates the phase singularity and vortex. [ABSTRACT FROM AUTHOR]