Search

Several observational programmes were conducted with ISO (Kessler et al., 1996) aiming at the investigation of the near- and far- infrared spectrum of the satellites of the giant planets. Thus, Jupiter's satellites Callisto, Io and Ganymede were explored mainly with the spectrometers, while the spectrum of Titan, Saturn's largest satellite, was investigated thoroughly by all the instruments. The analysis of the data has provided original and precious information on the satellites' surfaces and Titan's atmosphere in particular.

We describe a planar antenna structure consisting of two half-wave dipoles, which are backed by a metallic reflector to create an image of two more elements. The array produces rather a wide main beam, and is therefore used with a dielectric lens. The far-field pattern of the dipole liens antenna has cross-pol better than −20 dB, and side lobes below −13 dB over an octave band. The impedance at the feedpoint of the antenna is approximately 70 - j10 Ω at the center of the band.

Planar Nb-Nb Josephson Junctions (JJ's) have been developed to be used in submillimeter heterodyne mixers. Experimental mixing results show a System Noise Temperature around 1000 K with a best result of 800 K at an operating temperature of 1.5 K. Preliminary results at 900 GHz are reported. A strong temperature dependence of the mixer noise temperature has been observed.

For wavelengths 50μm the available detectors are far from ideal. Research and development of far infrared detectors for the mixing purpose are highly recommended.