Design and measurements of cryogenic MHEMT IF low noise amplifier for radio astronomical receivers

Design and cryogenic operation of an intermediate frequency (IF) low noise amplifier using a 0.15-µm InGaAs mHEMT process for Atacama Large Millimeter/Submillimeter Array (ALMA) is presented in this paper. The amplifier covers 4–12 GHz with small signal gain of 27±2 dB and effective noise temperature of 18–25 K when operating at 20 K. Different bias points are explored to investigate the potential of mHEMT amplifier operating with low dc power consumption. In this case, the amplifier can deliver 20±1 dB gain with effective noise temperature of 30 K at 4–8 GHz with 4.6 mW power consumption.