On-wafer measurements of S-MMIC amplifiers from 400–500 GHz

In this paper, we describe the design, simulation, and on-wafer measurements of Submillimeter-wave Monolithic Integrated Circuit (S-MMIC) amplifiers having gain in the 400-500 GHz range. A single-stage amplifier and two three-stage amplifiers with similar topology are presented, and have been fabricated in Northrop Grumman Corporation's (NGC) 35-nm InP high electron mobility transistor (HEMT) process. The circuits were fabricated using different indium channel compositions on different wafers, and comparison of the results based on the indium content will be presented. We have performed on-wafer S-parameter calibration and measurements using newly developed WR2.2 waveguide wafer probes from 325-508 GHz. We measured approximately 5 dB of gain for the single stage amplifier at 437 GHz, and approximately 10 dB of gain at 474 GHz for a three-stage amplifier, with over 9 dB of gain at 490 GHz.