Abstract: An antenna receives beams from telecommunication satellites in geostationary orbit close to the equator. The continuous concave reflecting surface of the reflector of the antenna has an equation deduced from a paraboloid by adding thereto the equation of a correction surface comprising a second order polynomial and a sum of N(2N−1) terms depending on distances between the projection of any point on the reflecting surface and N(2N−1) control points of a grid extending over a plane perpendicular to the plane of symmetry. The angular separation of the primary sources on a circular support with an inclination different from the angle of offset is less than approximately 3° for an aperture of more than 50°.

Abstract: The receiving antenna comprises at least two sectors or sections of paraboloids focusing the radiation onto their axes at points F.sub.1 and F.sub.2 respectively offset by a whole number of wavelengths of the received radiation. Each sector or section is associated with a helicoidal source located in its focal zone and having the same axis as that of the corresponding sector.

Abstract: The antenna particularly for domestic, collective or community installations, receives plural telecommunication beams and comprises a preferably paraboloidal fixed reflector with an axis of symmetry. At least one grating of annular diffraction members is substantially symmetrical with regard to the axis and is placed parallel to the reflector. The grating defines first and second focal points symmetrical to the axis towards which are susceptible to converge first and second beams directed substantially parallel to straight lines going through the centre of the grating and through first and second focal points respectively. A microwave head can sweep the focal plane along a focal line, or several microwave heads are positioned on a gantry thereby receiving or emitting plural beams, though the reflector is fixed.