Reflector antenna, especially for a communications satellite

Multiple reflector antenna comprising:

• a main reflector with a substantially circular aperture;
• a fixed feed system including a horn radiator which generates a rotationally symmetric radiation diagram, with a fixed polarization direction;
• and
• at least one auxiliary reflector for reflecting a radiation pattern from said fixed feed system onto said main reflector;
• wherein:
• the auxiliary reflector has a reflecting surface shaped as a partial surface of a rotationally nonsymmetric ellipsoid with a low numerical eccentricity;
• the auxiliary reflector is rotatable about a main axis thereof;
• and
• the auxiliary reflector illuminates the main reflector elliptically with an ellipticity that is substantially constant regardless of a rotational position of said auxiliary reflector.

A reflector antenna comprising:

• at least a main reflector having a double grid structure;
• first and second feed systems, each of said feed systems having
• a fixed feed section with a fixed position and a fixed polarization direction relative to said main reflector, said fixed polarization direction of said feed section of said first feed system being different from said fixed polarization direction of said feed section of said second feed system;
• and
• a horn radiator rotatably coupled to said fixed feed section, for emitting radiation from said fixed feed section, which radiation is reflected by said main reflector, said horn radiator having an elliptical output radiation pattern, and being rotatable relative to said fixed feed section about a longitudinal axis thereof.