Low Noise and Low Power Consumption Cryogenic Amplifiers for Onsala and Apex Telescopes

Christophe Risacher, Erik Sundin, Victor Robles, Miroslav Pantaleev, Victor Belitsky
As part of Onsala Space Observatory instrumentation activities, several low noise, low power consumption cryogenic amplifiers were developed for frequencies between 2 and 9 GHz based on GaAs HEMT MGFC4419G from Mitsubishi. Two narrow-band amplifiers were designed, one for 3.4-4.6 GHz with 2.7 K noise temperature and 30 dB gain, the other for 8.0-9.0 GHz with 5 K noise temperature and 26 dB gain, at 12 K ambient temperature. A broadband amplifier for 4-8 GHz demonstrates 5 K noise temperature
more » ... a gain of 26 dB with 2-stages, and 34 dB with 3-stages. Lastly, a 2-4 GHz amplifier is under current development. These amplifiers are currently used at the Onsala 20 m and 25 m telescopes, Sweden, both as front-end amplifiers and as IF amplifiers for mm-wave receivers and will also be used in the new APEX sub-millimetre telescope in Atacama Desert, Chile.