Thales

Thomson-csf Radant

Other

Thomson-csf

Thomson-cfs

Sws Sas

Contre Mesure Hyperfrequence

Sas Sws

Ecole Polytechnique

Avantix

Chekroun, Claude

Duran, Mario

Chekroun, Gilles

Claude Chekroun

Gilles Chekroun

Michel Soiron

Xavier Delestre

Thierry Dousset

Philippe Naudin

Marc-Yves Lienhart

Gerard Collignon

Benjamin Rouzeaud

Serge Drabowitch

Olivier Bohbot

Jean-Paul Largent

Georges Guillaumot

Michel Dubois

Roland Seneor

Jacques Dorey

Mario Duran

Marc Yves Lienhart

A device comprises at least: one rotary antenna including at least two parallel rectilinear waveguides; a radar emitting a continuous-wave microwave signal towards the emission guide of the antenna and receiving the signals from the guides of the antenna, which signals are captured by the movable beam, the received signals are the direct component I and the quadrature component; a stereoscopic video camera oriented in the same direction as the movable beam of the rotary antenna and able to record the clothing envelope of the individual, the envelope serving as a reference surface for the measurement of distances to the device; a processor that computes an SAR image of that portion of the body of the individual targeted by the radar and the video camera and who is possibly equipped with one or more objects, from signals received from the radar and the distances measured by the video camera.

Device for detecting objects borne by an individual

The antenna comprises at least one waveguide of rectangular section and a cylinder having an opening along a helical line, the cylinder having a relative rotational movement in relation to the waveguide placed inside the cylinder, the waveguide being open facing the inner face of the cylinder which forms a microwave short-circuit to close the guide, wherein two cavities are produced on each side of the guide, parallel thereto, over its entire length, the openings of the cavities being substantially in the plane of the opening of the guide. The invention applies, for example, to the detection of hidden objects carried by persons, in particular dangerous objects.

Rotary antenna, scanner using such an antenna, and device for inspecting persons

A device for detecting objects such as mines placed in a zone to be explored, the device being placed on a vehicle moving at a velocity V and including a panel on which a radiation set is arranged to transmit signals at an illumination frequency and to receive signals reflected from the zone, and a processing circuit to provide information about the presence of the objects after processing of the reflected signals, wherein the radiation set includes an alignment of antennas arranged transverse to the velocity V of displacement of the vehicle.

Device for detecting objects such as mines

The present invention relates to a device for detecting objects. The device comprises at least one microwave-frequency transmitter and one microwave-frequency receiver. The receiver makes a relative rotary movement about the transmitter, a signal being transmitted toward an individual for several positions of the receiver on the circle of relative rotation, the signals reflected by points of an object and received by the receiver at the positions being supplied to processing means in order to form a radar image. The receiver and the transmitter can be installed on a disk with a very low moment of inertia. The invention applies notably for the detection of weapons or explosives carried by persons.

Device for detecting objects, notably dangerous objects

The present invention relates to the production of reflectarray antennas, that is to say antennas consisting of a primary illumination source and a phase-shifting plate consisting of an array of cells each having a coefficient of reflection the phase of which is electronically controlled. According to the invention, each cell consists of a waveguide element closed at one of its ends by a dielectric substrate wafer carrying an electrical circuit formed by three parallel conducting strips. A variable capacitor, produced either in MEMS technology or by means of a ferroelectric element, is implanted by means of bonding wires on the electrical circuit etched on the substrate. The shape and the arrangement of the three parallel conducting strips constituting the electrical circuit and the way in which the variable capacitor is connected to this circuit make it possible to form, in the plane of the substrate, a phase shifter circuit, the phase shift of which may vary almost continuously over a wide range of variation. Advantageously, the phase shifter circuit thus formed occupies a small volume. The invention applies to the production of dual-polarization reflectarray antennas.

Phase-shifting cell having an analogue phase shifter for a reflectarray antenna

The present invention relates to a cylindrical electronically scanned antenna. The antenna has: a set of radiating guides () arranged in cylinder form for, producing the antenna beam (); An array () of 3 dB couplers is arranged in waveguide form. The inputs of the array are lit by a set of microwave feeds (). The output of each coupler is coupled to the input of a radiating guide (). An array of pairs of phase-shifting cells is, each coupled to a 3 dB coupler. An incoming wave from the microwave feeds () is phase-shifted by a controllable phase shift &#x394;&#x3c6;. The angular offset of the antenna beam () is dependent on this phase shift &#x394;&#x3c6;. The invention is typically applicable for equipping masts, in particular on ships.

Cylindrical electronically scanned antenna

An electronically scanned antenna working in a wide frequency band comprises at least: one reflector panel comprising an array of phase-shifters cells; one slotted waveguide illuminating the reflector panel by a microwave having a variable frequency f. The deviation &#x394;&#x3b8;of the direction of the wave emitted by the slotted waveguide, as a function of the frequency variations, countering the variation &#x394;&#x3b8;of the aiming direction of the wave reflected by the reflector panel. The disclosed antenna can be used especially in applications requiring compact or low-cost antennas.

Electronically scanned wideband antenna

The invention refers to array antennas consisting of a set of individual sources set out over the surface of the antenna and whose mechanical positioning is determined in such a way as to obtain the desired radiation pattern. The process according to the invention is designed to compensate for the positioning errors of radiating elements occurring when such an antenna is constructed. These positioning errors follow a law that is in theory random and whose result is known by determining the imperfection vector I whose components of real positioning errors measured for each feed of the antenna obtained comprising components forming values of an error function &#x3b4;(n) where n represents the index attributed to the radiating element in question. The process according to the invention consists in first measuring the positioning errors. It then consists in determining the spatial spectral components making up error function &#x3b4;(n). It finally consists in applying to each component an amplitude or phase modulation correction in order to compensate for the degradation of the error function &#x3b4;(n) on the obtained antenna radiation pattern F(&#x3b8;). The process according to the invention applies more particularly to antennas comprising radiating beams.

Process compensating for array antenna radiating element positioning errors

A dual polarization active microwave reflector with electronic scanning, configured to be illuminated by a microwave source to form an antenna. The reflector includes two imbricated waveguide arrays, the bottom of each waveguide array being closed by a phase shift circuit carrying out the reflection and the phase shifting of the wave that it receives. One of the two waveguide arrays is configured to receive a first polarization and the other waveguide array is configured to receive a polarization perpendicular to the first polarization.

Active dual-polarization microwave reflector, in particular for electronically scanning antenna

An active electronic scan microwave reflector, capable of being illuminated by a microwave source to form an antenna. The reflector includes a set of elementary cells arranged side by side on a surface, each cell including a phase-shifting microwave circuit and a conductor plate arranged substantially parallel to the microwave circuit, the phase-shifting circuit including at least two half-phase-shifters. One half-phase-shifter includes at least a dielectric support, at least two electrically conductive wires substantially parallel to a given direction, arranged on the support and bearing at least a two-state semiconductor element, the conductors being substantially normal to the wires, and two conductor zones arranged towards the periphery of the cell, substantially parallel to the control conductors. The control conductors can be at least three in number in each half-phase-shifter and can be electrically insulated from one half-phase-shifter to the next to control the state of all the semiconductor elements independently from one another. The geometrical and electrical characteristics of the half-phase-shifters are such that each of the states of the semiconductor elements corresponds to a given phase-shifting value of the electromagnetic wave reflected by the cell. The reflector further includes an electronic circuit controlling the state of the semiconductor elements.

Active electronic scan microwave reflector

A dual-band electronic scanning antenna, with an active microwave reflector. The antenna includes at least two microwave sources transmitting in different frequency bands and having opposite circular polarizations. An active reflecting array including elementary cells illuminated by the sources is provided. A polarization rotator is inserted between the reflecting array and the sources, changing the circular polarizations into two crossed linear polarizations. An elementary cell includes a conducting plane and first and second transverse phase shifters, the first phase shifter is substantially parallel to a linear polarization and the second phase shifter is substantially parallel to the other linear polarization. The conducting plane is placed substantially parallel to the phase shifters. The antenna is applicable in particular for microwave applications requiring two transmission bands moreover subject to very low-cost production conditions.

Antenna with double-band electronic scanning, with active microwave reflector

A microwave phase-shifter including a coupler in a waveguide form, at least one pair of phase-shifter cells, and a conductive strip positioned between each phase shifter cell and configured with a conductive plane to form a guided space where a wave cannot propagate. An incident wave entering a first input of the coupler is subdivided into two waves. Each of the waves are reflected on an elementary cell with identical phases to the incident wave and are recombined into a resultant phase-shifted wave prior to exiting the coupler by an output juxtaposed with the first input.

Microwave phase-shifter and electronic scanning antenna with such phase-shifters

An electronically steered scanning active microwave reflector, capable of being illuminated by a microwave source to form an antenna, comprises a set of elementary cells, each comprising a phase-shifter microwave circuit placed before a conductive plane. This phase-shifter comprises conductive wires or tracks positioned on a support, the wires or tracks each comprising at least two two-state semiconductor elements, for example diodes, and being connected to conductors by which the states of the diodes can be controlled independently of each other, it being possible for each of the diodes to be on or off. Thus, four possible states are obtained and the geometrical and electrical characteristics of the cell are such that a given phase-shift value of the microwave received corresponds to each of these states. Finally, microwave decoupling means are provided between the cells. These means consist, in particular, of waveguides formed between two neighboring cells. The walls of these waveguides are parallel to the polarization of the waves and the spacing between these waveguides is such that it prohibits the propagation of the wave.

Active microwave reflector for electronically steered scanning antenna

The invention pertains to the sensing and elimination of jamming signals transmitted by jammers towards radar antennas. According to the invention, we associate with a main space surveillance radar antenna an auxiliary antenna that is outfitted with a modulating filter which enables the sensing of jammers, and the elimination of jamming effects by opposing, to the secondary lobes of the main antenna corresponding to the jamming directions, corresponding secondary lobes which are appropriately amplified by the auxiliary antenna. The invention applies to anti-jamming of radar antennas with mechanical or electronic sweeps.

Device and method of using an auxiliary antenna outfitted with an

A microwave lens of the type described in the French patent No. 2,469,808 is adapted to operate with two crossed polarizations. To this end, each of the phase-shifting channels of the lens is subdivided into two subchannels, each of them being assigned to one of said polarizations. Each subchannel includes, in addition to phase-shifting panels, means for rotating by 90.degree. the polarization of the incident wave and impedance matching means.

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Gif sur Yvette, France

Claude Chekroun