A 21.5-50 GHz Low Noise Amplifier in 0.15-μm GaAs pHEMT Process for Radio Astronomical Receiver System

A fully-integrated Q-band low noise amplifier (LNA) for radio astronomical receiver system is implemented in 0.15-μm GaAs pseudomorphic high electron-mobility transistor (pHEMT) process. In order to extend the gain bandwidth, the R-C feedback technique is applied to make the impedance point closer to achieve the goal. The fabricated amplifier consumes 36-mW with a chip area of 2.5×1 mm². This LNA achieves a 22.5-dB peak small-signal gain with 6-dB bandwidth from 21.5 to 50 GHz. The measured noise figure is 3 to 4.5 dB within the effective bandwidth. The figure-of-merit (FOM) of this design is 7.5 GHz/mW, which has the potential of the earlier reported Q-band GaAs LNAs.