A multibeam antenna comprises a direct radiating array (DRA) comprising a plurality of radiating elements, a reflector facing the DRA so as to reflect a field generated by the DRA, and a DRA controller configured to control the plurality of radiating elements of the DRA according to a plurality of coefficients, such that the field generated at the DRA produces a plurality of beams when reflected by the reflector. The DRA controller is configured to determine the plurality of coefficients by using a bifocal antenna model to determine a field that would be produced by a subreflector and feed horn arrangement in an equivalent bifocal antenna configured to produce the plurality of beams, and determine the plurality of coefficients required to produce a similar incident field at the surface of the reflector. A method of controlling the multibeam antenna, and corresponding computer program instructions, are also disclosed.