Device for two-dimensional imaging of scenes by microwave scanning

A device for two-dimensional imaging of scenes through continuous microwave scanning by use of a fully mechanized, movable reflector-type directional antenna array configured as a dual-reflector antenna, said reflector-type directional antenna array comprising a rotationally symmetrical main reflector, a primary radiator assembly including one or a plurality of primary radiators and being arranged in the symmetry axis of the main reflector, said symmetry axis coinciding with the optical axis of the directional antenna array, and said reflector-type directional antenna array further comprising a rotationally symmetrical subreflector having small dimensions relative to the main reflector and having a vertex, the symmetry axis of said subreflector being inclined relative to the optical axis of the directional antenna array, there being provided first drive means operative to cause said subreflector which is inclined relative to the optical axis of the directional antenna array, to rotate at a rotational speed around the vertex and about the optical axis of the directional antenna array, and second drive means operative to cause a movement of the whole directional antenna array in a direction at least approximately vertical to the direction of the optical axis of the directional antenna array at a translational moving speed, and there being provided, an evaluation unit for generating from the received microwaves an image of the scene having first and second image dimensions, wherein the shape of the main reflector (1), the shape of the subreflector (2), the primary radiator (3), the distance between the primary radiator (3) and the subreflector (2) and the distance between the subreflector (2) and the main reflector (1) as focusing parameters for passive or active microwave scanning are attuned to each other in such a manner that, for a given scene distance (R), a selected focusing spot area of the field of view is obtained and a size of the field of view is controlled, the two drive means (8;17,18) are configured relative to each other in such a manner that the rotational moving speed of the subreflector (2) is larger than the translational moving speed of the whole directional antenna array, the focusing parameters and the moving speeds of the two drive means (8;17;18) are set in such a manner that a gapless, continuous scanning of the scene (13) is obtained with the aid of a focusing spot (12) moving, at the respective scene distance (R), in a trajectory which is combined from a trajectory (20) resulting from the rotation of the subreflector (2) and a trajectory (21) resulting from the movement of the directional antenna array transversely to the optical axis thereof and which at least approximately has the shape of a twisted cycloid, and the evaluation unit is configured in such a manner that, in the evaluation unit, as a consequence of the determinability and thus of the knowledge of the trajectories of the focusing spot (12) in the scene, the obtained image data are picked up synchronously with the position and are stored and, online or offline, are unified into an image and are represented or further processed.