Sensitivity performance of the SKA offset Gregorian reflector candidates with ideal feeds

A limited set of possible optics candidates for the SKA was recently proposed. This paper investigates the sensitivity performance of these offset Gregorian reflectors over tipping angle when illuminated by an ideal feed with varying edge tapers. The results show that feed down tipping together with a sub-reflector extension, that shields the feed from the ground radiation, achieves the best sensitivity performance. This is true for both unshaped and shaped reflector systems with the later performing slightly better due to higher aperture efficiencies.