Contoured-beam synthesis for array-fed reflector antennas by field correlation

A method is described for calculating the feed excitations of an array-fed reflector antenna for the production of a desired contoured beam. It is based on field correlation at the nearest reflector between the surface currents from selected stations in the field of view and the field radiated by the array. Mode coupling in the array is included in the formulation. The feed excitation is derived by satisfying constraints on the envelope of the copolar and crosspolar correlation functions through a minimax optimisation. Some preliminary results are presented for a simple contoured beam, which is realised using an open Cassegrain antenna and a 19-element circular-waveguide feed cluster.