Abstract: This is a review article discussing the latest
developments in beam-steering antennas at millimeter-wave frequencies
for Beyond-5G and 6G networks. This article classifies all the
beam-steering techniques described in the literature in four categories,
namely, phased arrays, quasi-optical systems, leaky-wave antennas, and
metasurfaces. An overview of the four classifications is presented with
a detailed comparison outlining the state-of-the-art and limitations of
different technologies.
Index Terms: Beamforming, Beam-Steering, Phased Array, Leaky
Wave Antenna, Quasi-Optical System, Metamaterial, Metasurface, 5G
Antenna, 6G Antenna.