Perforated dielectric antenna reflectarray for OAM generation

A new type of perforated dielectric flat reflectarray for the generation of OAM-carrying radio waves is presented. The reflectarray is introduced to transform the spherical wave emanating from the feed into a vortex beam after reflection through the azimuthal variation of the effective dielectric permittivity. Through perforating the substrate with holes of various diameters, an azimuthal variation of the permittivity is obtained and the corresponding azimuthal phase-compensation creates a vortex, thus an OAM wave is generated. The reflectarray antenna works in the millimeter frequency band, and can be used to generate the OAM states of ℓ =+1.