Figure 1: Operation of the new 3 mm SIS mixer prepared for antenna 3 at Plateau de Bure in a laboratory receiver with cooled optics. Minimum DSB receiver noise temperature is about 27 K. With a forward efficiency of 93% at the 15 m telescopes, in good weather condition such receiver still contributes more than 50% of the system noise temperature. Further improvement of the mixer is in progress.
Figure 2: Receiver performance with a new 3 mm mixer with an E plane stub. This is a spare Plateau de Bure receiver with ambient temperature optics and a diplexer for LO injection. Later this mixer was installed in the 30 m telescope receiver.
Figure 3: Operation of the receiver with the new 1.3 mm SIS mixers prepared for the dual channels receivers of Plateau de Bure antennas 1-3. Receiver structure is similar to the real receiver: optics is cooled and the local oscillator is injected by a coupler. This is the first design of SIS junctions with the fully optimized integrated circuit.