Abstract: A duplexing circularly polarized composite antenna comprises at least one pair of radiator elements supportings orthogonal (vertical and horizontal) linear polarization. One radiator element is fed with a signal with a phase difference of 90.degree. relative to the signal fed to the other radiator element. Each radiator element transmits and/or receives signals at two different frequencies having orthogonal polarization. One radiator element operates at a first frequency with vertical polarization and a second frequency with horizontal polarization. The other radiator element operates at the first frequency with horizontal polarization and at the second frequency with vertical polarization.

Abstract: A large scan antenna, particularly for embarked use on board a satellite and for operation in the ultrahigh frequency range, of the type formed of a feed and a main fixed secondary reflector, the antenna being readily foldable into a launching configuration with a minimum of component elements, and comprising at least one guide G each formed of a first and a second parabolic secondary reflectors (12, 13) aligned optically along the axis of the wave guide G between the feed (10) and the main reflector (15), said wave guide G being on the one hand variable in length by moving at least one (13) of said secondary reflectors with respect to the other (12) along the axis (14) of the wave guide G, and on the other hand, rotatable about the axis (11) of the feed (10).

Abstract: An antenna for receiving or transmitting electromagnetic waves with circular polarization or, in certain configurations, linear polarization. The antenna element is low-cost, wide-band and medium-gain broadside antenna element which may be used alone or in arrays. One embodiment disclosed comprises a wire or micro-strip conductor outlining a cruciform shaped loop parallel to a conductive plane from which it is separated by a dielectric layer. The lengths and widths of the branches of the cruciform loop are chosen to be .lambda.g/2 and .lambda.g/N respectively, where .lambda.g is the guide wavelength of the radiative transmission line formed by the conductor and plane. The antenna element is applicable to mobile earth-bound terminals for selective communications, for example.

Abstract: The invention provides an antenna for transmitting or receiving closely spaced multibeams with very low level sidelobes comprising, for each beam feed, a primary feed feeding one or more main elements surrounded by secondary elements some of which are shared between several adjacent beam feed, the power supplied by the primary feed being distributed to the different elements by means of couplers. According to the invention, each shared element is fed by each of the power transmission lines feeding the main element (E1, E'1) of said adjacent beams through a coupler, each transmission line of a secondary radiating element (L2, L'3) comprising at least two couplers (C1, C2) in series.

Abstract: A double grid reflector antenna for radiating different signals having pure linear orthogonal polarization comprises a couple of identical and superposed reflecting grids. One of said grids has been rotated its boresight to disengage its focus from that of the other, and feeds are set in the focal plane of the respective grids. The front grid reflects indifferently either horizontal or vertical polarization, while transmitting the orthogonal polarization to be reflected by the rear grid.