A High-Order-Mode OAM Patch Antenna with High Gain and Low Divergence

Abstract

A high-order-mode two-feed orbital angular momentum (OAM) patch antenna at Ka-band is proposed in this paper. The circularly polarized OAM patch antenna has an impedance bandwidth of 23.7% with more than 10-dB return loss. A vortex beam carrying $l=\pm 1$ OAM mode is generated with a mode purity over 85% from 26.5 GHz to 33 GHz. Additionally, by loading a low-profile lens, the maximum gain can be improved from 6.7 dBic to 15.7 dBic, and the beam divergence angle converges from 37° to 6°.