Broadband Orbital Angular Momentum Beam Generation Based on the Discrete Dielectric Lens antenna

The electromagnetic waves carrying orbital angular momentum (OAM) have great potential for applications. Broadband OAM beams are the preference in many sectors. Existed studies show that the beams have been widely explored. Considering the narrow bandwidth of the existing lens antenna carrying OAM we engineer a new discrete dielectric lens (DDL) antenna carrying broadband OAM. The antenna adopts a dielectric unit with an anti-reflection structure and is a cross-shaped air column. By increasing the phase compensation range, the bandwidth of the vortex beam is effectively increased. A broadband OAM generator is designed based on the DDL from 22 to 30 GHz. A proof-of-concept example was proved and validated by simulation. Above 31% vortex beam bandwidth and 64.6% OAM average energy weight are measured throughout the entire design band. This kind of structure offers an alternative mechanism to realize broadband high-efficiency microwave, millimeter-wave, terahertz, or optical OAM generation and can hereafter get position in high-capacity communications and imaging.