Analysis of a uniform rectangular array for generation of arbitrary orbital angular momentum (OAM) modes.

Using the array antenna theory, theoretical radiation and near-field characteristics of a uniform rectangular array (URA) for high-gain or wide-beamwidth orbital angular momentum waves have been rigorously studied. Closed-form weighting factors of URA elements are derived based on the Hankel transform proposed for aperture antennas. Simulated radiation patterns and near-field distributions show that a URA configuration is superior to a uniform circular array in terms of antenna gain, beamwidth, and beam-scanning capability. [ABSTRACT FROM AUTHOR]