a D-band LNA is realized in OMMIC 70-nm GaAs mHEMT. The average gain of 26.7 dB and global noise figure below 6.1 dB are attained with low power consumption of 28 mW. The wide bandwidth of 40 GHz is achieved by T-shape input and output impedance matching and dual T-shape interstage matching. Moreover, the output return loss is enhanced to be better than 9 dB by the common-source stage and larger transistor size.