The inventive device enables to ensure its compactness, that is, a minimum thickness at a high antenna efficiency of an antenna in the frequency range 10.7-12.75 GHz. This technical effect can be achieved because the antenna comprises a main reflector (1), at least two feeds (2) and at least two sub-reflectors (3). Each sub-reflector is provided with such a shape of its external surface that ensures reflection of the feed directional pattern central beam to the edge of the main reflector and reflection of a lateral beam to the central area of the main reflector, the sub-reflector adjoining surfaces being truncated.