Low nose submillimetre SIS receiver for 30 m IRAM radiotelescope

A low noise SIS mixer receiver is prepared in IRAM for the operation at 0.8 mm wavelength on the 30 M telescope at Pico Veleta in Spain. For this receiver a new fixed-tuned waveguide SIS mixer is developed. This mixer is able to operate in a wide band being fixed tuned. The present mixer design uses relative large NbAIoxideNb SIS junctions (1-2 ¿2) in which parallel inductive tuning is implemented with quasi-lumped elements. Experimental measurements agree with model predictions of the new SIS mixers performance. At the IRAM 30-m radiotelescope the best receiver DSB noise temperature achieved in the 0.8 mm band is about 70 K It is believed that it is the first wide band receiver with a fixed tuned submillimeter SIS mixer on the radiotelescope with the lowest noise temperature published for the moment.