Beam squint in parabolic reflector antennas with circularly polarized feeds [Antenna Designer's Notebook]

The beam squint phenomenon is an important design issue for modern reflector antennas, because it can affect the antenna pointing performance. For long-distance communications, like satellite or deep-space communications, this effect must be care- fully taken into account in order to avoid any degradation. In some design considerations, one may use the squint phenomenon to one's advantage in separating two RHC- and LHC-polarized beams. Squint was previously observed in offset parabolic reflectors with an on-focus circularly polarized feed [l], such as that shown in Figure 1. It must be emphasized that this squint only occurs for antennas with circularly polarized feed, but not for those for which the feed is linearly polarized.