For two-dimensional imaging of scenes through continuous passive or active microwave scanning, use is made of a fully mechanized directional antenna array comprising a main reflector (1), a primary radiator array (3) and a subreflector (2) having a small size in comparison to the main reflector and being tilted relative to the optical axis (7) of the directional antenna array. First drive means (8) are operative to rotate the subreflector (2) about the optical axis (7), and second drive means (17,18) are operative to move the total directional antenna array in a direction approximately vertical to the optical axis (7). The moving speed of the subreflector (2) is very high in comparison to that of the total directional antenna array. The shape of the main reflector (1), the shape of the subreflector (2), the primary radiator (3), the distance between primary radiator and subreflector and the distance between subreflector and main reflector as focusing parameters are attuned to each other in such a manner that, for a given scene distance, an optimum focusing and an optimum size of the field of view are achieved. The focusing parameters and the moving speeds of the two drive means are set in a manner allowing for a gapless, continuous scanning of the scene with the aid of the focusing spot (12) moving at the scene distance. Applicability in remote investigation, particularly in earth observation and in safety technology.