Beam Modeling of Reflector Antennas across Elevation

We present methods for predicting the beams of reflector antennas across elevation, given measured surface and alignment errors at only a few tilting angles. Specifically, the Characteristic Basis Function Pattern (CBFP) method is applied, where we interpolate over the model coefficients to predict an unknown pattern at a desired elevation. We also describe a method for interpolating the geometric reflector surface and feed alignment errors across elevation. The methods are evaluated and compared using preliminary photogrammetry data of a 15-m SKA antenna. We show that a combination of the methods can result in a maximum error in the predicted beam of under 1%.