Cryogenic LNAs for SKA band 2 to 5

Four ultra-low noise cryogenic MMIC LNAs suitable for the Square Kilometer Array (SKA) band 2 to 5 (0.95–13.8 GHz) have been designed, fabricated, packaged and tested. The LNAs are based on 4×50, 8×50 and 16×50 μm HEMTs, designed for stable cryogenic operation, allowing the combination of good noise performance and return loss. The lowest noise temperatures measured in the four bands were 1.0 K, 1.2 K, 1.6 K and 2.6 K, respectively.