Cryogenic performance of a GaAs MMIC distributed amplifier

A three-stage GaAs MMIC distributed amplifier chip which was specially packaged in a two-chip, six-stage amplifier for cryogenic operation from 1 to 10 GHz is discussed. When immersed in liquid nitrogen, a fourfold reduction in amplifier noise is observed over the 4-GHz to 8-GHz frequency range. The cryogenic amplifier package is described, and the test configuration is explained. The reduction in amplifier noise is in agreement with the generally observed scaling with ambient temperature (in Kelvin) for discrete GaAs FET amplifiers.<
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