Design of a horn lens antenna for OAM generation

A horn lens antenna designed for the generation of OAM-carrying radio waves is presented. The conventional horn antenna is integrated with a single-layer perforated planar dielectric lens by covering its aperture. Through varying the diameter of holes, an azimuthal variation of the permittivity is obtained and the corresponding azimuthal phase delay creates a vortex, thus an OAM wave is generated. The lens antenna works in the millimeter frequency band, and can be used to generate the OAM states of ℓ =+1 or -1.