Low-noise W-band amplifiers for radiometer applications using a 70nm metamorphic HEMT technology

W-band low-noise amplifier (LNA) MMICs have been developed using a 70 nm metamorphic HEMT (MHEMT) technology. The short gate length in combination with the high indium content of 80% in the channel lead to a maximum transconductance of 1500 ms/mm for a 2x30 µm device. This results in a transit frequency ft of 290 GHz. Two- and three-stage amplifiers were realized in coplanar waveguide technology (CPW) and achieved a small Signal gain of 13 dB and 19 dB, respectively. The noise figure at room temperature of both LNAs was below 3 dB. The on-wafer measured output power at the P-1dB as compression point was 5 dBm. A modification of the three stage LNA showed a noise figure of 2.5 dB, with a small signal gain of 15 dB at 94 GHz.