Développement de composants SIW dans la bande 3 d'Alma (84-116 GHZ) et conception d'une jonction orthomode (OMT) dans la bande 1 d'Alma (31-45 GhZ) en technologie guide d'onde

Millimetre-wave radio astronomy has undergone rapid growth since it was first developed at the beginning of the 1970s. Thus it has contributed considerably to the understanding of cosmological and astrological phenomena. One source of information on the physical and chemical state of interstellar clouds is through both continuum and the emission lines of interstellar molecules in the millimetre waves. From this data, it is possible to identify a molecule by the frequency of the lines for different transitions while the amplitude and the Doppler shift give us information on the cloud's kinetic state, its density and its temperature. Through radio telescopes, astronomers can penetrate the interior of interstellar molecular clouds, and glean information on how stars are formed. The millimetre-wave receivers used in radio telescopes with parabolic or spherical reflectors are cooled to temperatures between 4K and 77K. Because this considerably reduces thermal noise, it is possible to capture very weak amplitude signals from space. The ALMA (Atacama Large Millimeter Array) project – a network of 80 radio telescopes set up at an altitude of 5200 metres, in Atacama, Chile, each with a 12 metre, parabolic antenna – operates at cryogenic temperatures. These radio telescopes will operate in 10 millimetre and sub-millimetre bands (31 GHz to 1 THz). ALMA will enable research into the physics of the cold universe, regions that are optically dark but shine brightly in the millimetre portion of the electromagnetic spectrum. Providing astronomers a new window on celestial origins, ALMA will probe the first stars and galaxies, and produce detailed images of the formation of planets and stars, as being formed in gas clouds near the Sun, in both continuum and the emission lines of interstellar molecules. It will observe galaxies in their formative stages at the edge of the universe, which we see as they were roughly ten billion years ago. ALMA will operate at wavelengths of 0.3 to 9.6 millimeters and will provide astronomers unprecedented sensitivity, angular resolution and spectral resolution.