6 – 10 GHz Cryogenic GaAs pHEMT LNA MMIC

This paper demonstrates a cryogenic broadband GaAs pHEMT LNA MMIC. The LNA MMIC was designed by using modified GaAs pHEMT model, which includes the thermal characteristics of each device material. The MMIC was fabricated by using a commercial 0.25μm GaAs pHEMT process. The fabricated LNA MMIC achieved a noise figure of less than 0.3 dB and an associated gain of over 15dB at 6-10 GHz and 77K operating temperature. The corresponding return losses are better than 10 dB. At 7GHz, the LNA realized a noise figure of 0.11dB (a noise temperature of 7.7K) and an associated gain of 20dB. The power consumption is 25 mW. The MMIC occupied 1.4mm ×1.0mm. These performances are the same level as those of LNAs at 10K-20K operating temperature.