Abstract: A double-reflector microwave antenna of the Gregorian optics family and capable of providing an elliptical beam with a major axis that may be oriented in any desired direction of space by rotation of the sub-reflector about an axis. By adding an additional degree of freedom, that is, an independent translation of the sub-reflector and/or the main reflector along respective axes, a considerable degree of reconfigurability of the shape of the beam may be realized. In particular, the axes of the beam may be widened to vary the ratio between the axes of the elliptical beam for any orientation of the major axis or to obtain a circular beam. The inventive antenna is particularly suitable for use as on board satellites with frequency re-use in an operational environment with one or more simultaneously active beams.

Abstract: A method of manufacturing dichroic antenna structures, which makes use of a projector mounted on the mobile arm of a computer-controlled machine to project the shape of selective antenna elements on the surface of an insulating layer, clad with a metallic layer covered in turn with a photographic emulsion. Development and chemical etching of the excess conductive parts are then carried out.

Abstract: This structure for a dichroic antenna can be used in a reflector antenna capable of operating at the same time at two different frequencies or with two orthogonal polarizations, and presents mechanical characteristics allowing its use on board the satellites. The structure, suitable for a subreflector, comprises a plurality of layers with high mechanical stiffness in the external part, followed by layers with low dielectric constant and one or a plurality of metallic grids in the most internal part, separated by low-dielectric constant layers.