NOVEL METHOD FOR GENERATING ELECTROMAGNETIC VORTEX WAVE

Electromagnetic (EM) vortex wave carries orbital angular momentum (OAM), which has been proposed for improve anti-interference performance, spectral efficiency, and message capacity in radio communications. Multiple sub-channels of propagation are achieved by different twisting degrees of EM wave. In order to develop the theory and technique of the OAM, works must be done to study the generation of vortex wave. There exist several devices to generate vortex wave, such as phase plate, holographic diffraction gratings, spiral reflectors, and antenna arrays. In this paper, based on typical parabolic antenna, a new approach to generate vortex wave carrying OAM in radio frequency through coating specific controllable complex dielectric constant material on parabolic antenna is introduced. From the results of the proposed antenna, we conclude that parabolic antenna with materials arranged by a specific rule on the reflector has capacity of generating an EM wave with clockwise and anti-clockwise phase distributions around beam-axis. The new method generating OAM is simple and suitable to be well applied in wireless electronic technology.