Thomson-csf

Jean Rannou

Emile Pouderous

Alain Bizouard

Pascal Gilbert

Henri Perron

William Luther

Marcel Godet

Christian Boulingre

Michel Grozellier

A layer (30) absorbing transmitted radiation, placed between an antenna (10) and a radome (20) and extending parallel to the surface of the antenna at a close distance thereto, the absorption coefficient of said absorbing layer varying between a minimum value in the center of the radiating surface and a maximum value at the periphery of said radiating surface. The absorbing layer may in particular be formed by a central area (31) with a zero or virtually zero absorption coefficient surrounded by a peripheral area (32) with a constant absorption coefficient. It may also be formed by a succession of concentric areas exhibiting respective absorption coefficients increasing from the center to the periphery. In addition to the reduction of the radome effect, said structure reduces significantly the radar cross section of the assembly when the latter is the target of a radar.

Device for reducing the radome effect with a surface-radiating wideband

A device for waveguide excitation in circular polarization comprising a microwave feed line along which a transverse electromagnetic wave travels, a waveguide and a radiating element fed by the line for radiating a wave which excites the waveguide in circular polarization.

Antenna comprising a device for excitation of a waveguide in the

A method of producing a material for absorbing ultra-high frequency waves from a starting porous material having closed cells includes the steps of immersing the porous material into a fluid having a liquid component, suspended carbon, and a dissolved polymerizable binder, applying sufficient pressure to the fluid to open the closed cells of the porous material, allowing the fluid to disperse into the opened cells, removing the porous material from the fluid, drying the porous material to remove the liquid component, and closing the cells by polymerizing the binder.

Method for the manufacture of material absorbing ultra-high frequency

The present invention relates to reciprocal junction devices between independent coaxial lines and concentric coaxial lines. As many elementary junctions as there are independent lines, less one, are required. Each elementary junction involves a two-wire line zone and two parts which establish a progressive transition between the two-wire line and, at one end, the independent coaxial line and, at the other end, the concentric coaxial lines.

Reciprocal microwave junction device

The invention relates to wide-band, plane, spiral antennas. A conductive arm is arranged spirally in a plane close to a reflector. A resonator member positioned at the centre and in front of the spiral assists the area opposite which it is situated to radiate at high frequencies, to the detriment of the peripheral areas. An absorbent member whose thickness increases from the centre to the periphery increases this effect even further.

Wide-band spiral antenna

An omnidirectional wide-band antenna which operates with simultaneous horizontal and vertical polarisation consists of two truncated conductive cones which operate as a bi-conical antenna and each truncated cone is associated with a conductor array perpendicular to the axis of the cones. The conductors are in the form of logarithmic spirals.

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Paris, France

Jean Rannou