InP HEMT-based, cryogenic, wideband LNAs for 4-8 GHz operating at very low DC-power

We present cryogenic broadband amplifiers for 4-8 GHz with very low dc-power consumption and low noise. Two different amplifiers were designed and manufactured, one of which was based on in-house InP devices and the other on commercial GaAs devices. When cooled to 15 K, the InP-based amplifier shows an input noise temperature of 3.9 K at a dc-power consumption of 3.7 mW. The GaAs-based amplifier shows an input noise temperature of 6.5 K at a dc-power consumption of 23 mW.