Series-feed UCA antenna for generating highly azimuthal symmetric OAM Beam for unmanned aerial vehicles

This paper presents a new approach to producing a conical beam (CB) with highly azimuthal symmetry through a series-feed uniform circular array (UCA) antenna using circularly polarized (CP) elements and the orbital angular momentum (OAM) technique. Most previously proposed antenna designs for generating CB radiation patterns using mode-combining techniques have complex structures and high costs. The proposed antenna utilizes the inherent properties of OAM waves to generate a conical-shaped beam with simplicity and compactness. The UCA antenna utilizes CP elements, which are rotated to provide the desired far-field phase for generating the OAM beam. This design achieves extensive signal coverage and is highly efficient, with minimal spurious radiation and low insertion losses. The experimental measurements validate that the OAM beam produced by the UCA antenna has high azimuthal symmetry at 6GHz. The OAM beam generated exhibits high mode purity and a peak gain of 10dBi, with a divergence angle of ± 22°.