OMMIC 70nm-mHEMT LNA design

This paper describes our progress in the design of cryogenic LNAs using OMMIC 70nm mHEMT for the Square-Kilometer-Array (SKA) project and the Shanghai 65-Meter radio-astronomical telescope. Different LNAs covering the aggregate 1∼40GHz frequency range are designed and measured on-wafer at room temperature, and Tn for the 1∼10, 5∼15, and 10∼40GHz LNAs are 80K, 90K, and 120K, respectively, with the gain all larger than 20dB. One 1∼10GHz LNA chip is then packaged and tested cryogenically, and the noise temperature improvement factor is 6∼8, which is smaller than what can be obtained from the WIN pHEMT. Performance repeatability among different chips has been carried out.