Abstract: A low noise amplifier device for receiving a radio frequency signal from a satellite contains an amplifier kept in a sealed chamber in a cryostat, and a cryogenic cooler mounted on the outside of the cryostat. The amplifier is: maintained in the sealed chamber attached to a cold finger of the cryogenic cooler, made of a material with good heat conductivity and without direct contact with the wall of the cryostat; connected to the input and output coupler, each traversing the wall of the cryostat; functional at room temperature and at least one cryogenic temperature well below room temperature; and the sealed chamber of the cryostat contains a gas at a pressure between a pressure close to the pressure outside the cryostat and 0.1 millibar.

Abstract: A radiofrequency amplifier includes a low noise amplifier (25) maintained in a hermetic cryostat structure (11) cooled by a cold head (30) and in which is maintained a low grade vacuum. The low noise amplifier receives signals from an input coupler (23) and transmits the signals through an output coupler (26). The input and output couplers are made, for a structural part, of a material with thermal conductivity equal or less than 50 W/m·K, and, for an electrically conductive part, of plating on at least one of the faces of the structural part, with a material with electrical conductivity more than 10E7 Siemens/m. The cold head includes at least two stages whose cold terminations are at different cryogenic temperatures, a base stage operating at a temperature close to the temperature at which the low noise amplifier must operate and at least one intermediate stage operating at an intermediate temperature.

Abstract: A low noise amplifier device for receiving a radio frequency signal from a satellite contains an amplifier kept in a sealed chamber in a cryostat, and a cryogenic cooler mounted on the outside of the cryostat. The amplifier is: maintained in the sealed chamber attached to a cold finger of the cryogenic cooler, made of a material with good heat conductivity and without direct contact with the wall of the cryostat; connected to the input and output coupler, each traversing the wall of the cryostat; functional at room temperature and at least one cryogenic temperature well below room temperature; and the sealed chamber of the cryostat contains a gas at a pressure between a pressure close to the pressure outside the cryostat and 0.1 millibar.