A 2.5-5 GHz Cryogenic GaAs pHEMT MMIC LNA with an Average Noise Temperature of 2.5 K

This paper presents a broadband 2.5-5 GHz cryogenic low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) implemented on 250 nm GaAs pHEMT process. The three-stage LNA MMIC was assembled in a chip-on-board configuration and measured at physical temperature of 16K. The amplifier provides an average noise temperature of 2.5 K with an average gain of 37 dB while consuming 7 mW DC power. A low power mode was also demonstrated, achieving 32.8 dB average gain and 4.3 K average noise temperature while consuming only 2.6 mW. Measurements on three samples confirm consistent cryogenic behavior of the proposed LNA. The results indicate that the presented GaAs pHEMT MMIC has achieved ultralow noise at cryogenic temperature, and is a well candidate for superconducting quantum computing which requires a large number of parallel LNA in the near future.