Design and performance of OAM modes generated using dipole arrays with different feeds

This paper presents 2 types of 4-element arrays generating mode 1 orbital angular momentum (OAM) radio beams at 73 GHz (E-band) using dipole antennas. We investigate the performance of a corporate feed array that uses 2 T-junction dividers and that of a series feed array which uses only 1. Design details are shown in the paper and both of the arrays are fabricated on 0.127 mm FR4 substrate with relative permittivity of 3.65 and loss tangent of 0.013. Fabricated antennas are measured using an Agilent vector network analyzer for input match and NSI 700S-360 spherical near-field scanner for radiation patterns. The results are compared with ANSYS HFSS at 73 GHz.