A DC-3 GHz cryogenic AlGaAs/GaAs HBT low noise MMIC amplifier with 0.15 dB noise figure

This work reports on the lowest noise figure so far obtained for a bipolar monolithic microwave integrated circuit (MMIC) amplifier. The amplifier is based on an ultrahigh current gain AlGaAs/GaAs HBT technology with peak DC beta and f/sub T/ of 800 and >40 GHz, respectively. At a cryogenic temperature of 12 K, the HBT LNA achieves 36 dB gain and less than 0.2 dB noise figure over a DC-2 GHz bandwidth. The minimum amplifier noise figure is 0.15 dB. The wide band HBT MMIC LNA has direct applications to high speed superconductor digital communications as well as deep space receivers and radiometers.