Abstract: The present invention relates to a device for receiving/transmitting electromagnetic waves with omnidirectional radiation of the type comprising:

Abstract: The present invention relates to a device for the reception and/or the transmission of electromagnetic signals comprising at least two means of reception and/or of transmission of electromagnetic signals of the slot-fed antenna (11a, 11b, 11c, 11d) type and means of connection for connecting at least one of the said means of reception and/or of transmission to means of utilization of the multibeam signals, in which the means of connection consist of two feed lines (12, 13) connected by a connection element to the utilization means (P), the two lines being coupled electromagnetically with the slots of the slot-fed antennas, each line terminating in a switching element (14, 15) arranged in such a way as to simulate, as a function of a monitoring signal, an open circuit or a short circuit at the extremity of one of the lines and a short circuit or an open circuit at the extremity of the other line so as to obtain different radiation patterns.

Abstract: Planar antenna carried by a substrate comprising an annular slot, which is dimensioned to operate at a given frequency and which is fed via a line (2), such as a microstrip line, in a short-circuit plane of which the slot is situated.

Abstract: A device for sending and receiving electromagnetic waves comprises an antenna with a waveguide, a sending card and a receiving card. The sending card and the receiving card each extend essentially from the waveguide, and therefore from the antenna axis, in a plane perpendicular to this axis and between them form an angle greater than 90°.

Abstract: The invention relates to a device for emitting and/or receiving electromagnetic waves comprising a lens bringing a plurality of directions defined by the radiation space of the lens into correspondence with a plurality of focusing points defining a focusing surface of the lens, the lens comprising a shaped volume of dielectric material. According to the invention, the dielectric material comprises a granular agglomerate defined by a homogeneous or quasi-homogeneous distribution of granules of the same type and of small size with respect to the wavelength (&lgr;R, &lgr;T) of the electromagnetic waves to be received and/or emitted by the said device, the said granules being held under pressure in the said volume by holding means shaped according to the said volume. The invention also relates to a communications terminal comprising a device according to the invention.

Abstract: The present invention relates to a device for transmitting and/or receiving electromagnetic waves comprising at least one antenna with at least one radiating element transmitting and/or receiving signals of given polarization and a feed array produced in microstrip technology consisting of lines devised so as to give parasitic radiation. In this case, the feed array is devised and dimensioned in such a way that the parasitic radiation has the same direction and the same polarization as the radiation of the antenna and combines in-phase with the said radiation of the antenna.

Abstract: The invention concerns an electromagnetic wave transmitter/receiver device, comprising a body (18), characterised in that it comprises in combination: a receiver plate (16) incorporated in the body (18) including a first array of n radiating elements (301, 302, 303, 304) with a microstrip structure for receiving electromagnetic waves; means for transmitting (19, 20, 22, 23, 24) electromagnetic waves with longitudinal radiation defining a radiation axis for transmitting electromagnetic waves, said means including excitation means (24) for exciting the longitudinal radiation means (19, 20, 22, 23); said radiation means being substantially of constant cross-section in the body (18), perpendicularly intersecting the receiver plate (16) in a circular aperture around which are symmetrically arranged said radiating elements (301, 302, 303, 304), said receiving and transmitting means being arranged such that their respective phase centres are substantially arranged in a so-called focusing zone.

Abstract: The invention relates to a system of antennas for tracking nonsynchronous satellites (21, 22) along predefined trajectories. It is characterized in that the said system includes at least first (11) and second (12) transmitter/receiver elements moving in the vicinity of the focusing surface of the system (1) along a line of focal points, the first element (11) actively tracking a first satellite (21) and the second element (12) standing by to actively track a second satellite (22). Particular application to the tracking of nonsynchronous satellites, in particular low- and mid-orbit satellites, and of geostationary satellites.

Abstract: The present invention relates to a T-circuit produced using microstrip technology with two branches (2, 3) of identical length L2 comprising a phase-shifting element (6) producing a given phase shift &PHgr; by extending one of the branches, the T-circuit operating in broadband, the circuit comprises at least one elbow (4) extending the branch (3) without the phase-shifting element and the length L2 is equal to a multiple of &lgr;g/2 where &lgr;g is the guided wavelength.

Abstract: The present invention relates to a source antenna for transmitting/receiving electromagnetic waves comprising means for transmitting electromagnetic waves with longitudinal radiation operating in a first frequency band and means for receiving electromagnetic waves, characterized in that the means for receiving electromagnetic waves consist of a first array of n radiating elements operating in a second frequency band and a second array of n′ radiating elements operating in a third frequency band, the first and second arrays and the longitudinal-radiation means having a substantially common phase center and the radiating elements of the first and second arrays being arranged around the longitudinal-radiation means.

Abstract: The invention relates to a device for emitting and/or receiving electromagnetic waves comprising a lens bringing a plurality of directions defined by the radiation space of the lens into correspondence with a plurality of focusing points defining a focusing surface of the lens, the lens comprising a shaped volume of dielectric material.

Abstract: Wireless transmission process and apparatus include a frequency diversity process for carrying out spectral spreading of a modulated SHF (Super High Frequency) carrier. The modulated SHF carrier transports information between a transmitter and at least one receiver. The frequency of the SHF carrier is varied continuously in a specified band so as to transmit to the receiver a signal having a spectrum containing a plurality of frequencies representing a plurality of uncorrelated signals each transporting the information to be transmitted.

Abstract: The present invention relates to a process and a device for the wireless transmission of a signal S.sub.1 between a transmitter and at least one receiver.According to the invention, at the sending end:a first carrier S.sub.2, of frequency F.sub.2, situated in the VHF (Very High Frequency) range, is frequency-modulated by the signal S.sub.1 to be transmitted, and thena second carrier S.sub.3 of frequency F.sub.3, situated in the SHF (Super High Frequency) frequency range, is amplitude-modulated by a modulating signal S.sub.2m. resulting from the frequency modulation of the carrier S.sub.2 so as to transmit an amplitude-modulated signal S.sub.3m to the receiver,and at the receiving end:amplitude demodulation of the signal S.sub.3m is performed so as to recover the signal S.sub.2m, and thenfrequency demodulation of the signal S.sub.2m is performed so as to recover the signal S.sub.1.

Abstract: A feeder for a microwave antenna system which can be integrated together with electronic circuitry on a common circuit board. A slot antenna, preferably shaped as an annular slot, is provided on the circuit board, and can be etched on the backside of the circuit board, which is normally a ground plate. The antenna system can be used for reception of DBS signals.

Abstract: A helical antenna system for receiving simultaneous signals with different polarizations, with the aid of helical feeders and without gain degradation. Two or more helical feeders are provided for each polarization direction.

Abstract: An antenna system capable of receiving electromagnetic radiation having either right or left helical polarization, and either vertical or horizontal linear polarization includes an energy concentrator which concentrates energy at a focal point. A helical antenna is arranged in the proximity of the focal point. A first switch switches the helical antenna to a backfire mode of operation and a second switch switches the helical antenna to an end fire mode of operation. A control mechanism controls the switches to select the nature of the polarization.