Generation of Vortex Beams with Mixed Modes based on Non-Uniform Circular Array

Vortex beams with mixed modes refer to the superposition of single vortex beams with different OAM modes. In order to facilitate the researches on the transmission characteristics, receiving methods, and demultiplexing methods of the vortex beams with mixed modes, it's necessary to design simple devices to generate them. According to this, this paper proposes a novel non-uniform circular array (NUCA) for generating vortex beams with mixed modes based on a phase modulation method. This method is corresponding to the feeding network which only needs equal power feeding. And the element of the NUCA is an E-type broadband air dielectric antenna working at 1.9-2.4GHz, which has the characteristics of wide frequency band, light weight, and easy processing. So that the device in this paper is simple and effective to generate vortex beams with mixed modes.