Beam squint in axially symmetric reflector antennas with laterally displaced feeds

Numerical calculations have been carried out and the beam squint for circular polarized excitation has been measured using a 100 m telescope. The telescope was operated in the Gregorian mode, where the equivalent focal length equals 387.5 m. The feed horn was laterally displaced by 1.364 m from the optical axis at the system focus. Good agreement was obtained between the numerical calculations and the experimental results. The authors found a shift of the two radiation patterns of ≃2 arcsec. The orientation of the beam squint in the configuration with a laterally displaced feed is different from the orientation in offset reflector antennas