A 140GHz power amplifier with 20.5dBm output power and 20.8% PAE in 250-nm InP HBT technology

We report a high-efficiency D-band power amplifier in 250nm InP HBT technology. The design has three common-base stages and a low-loss 4:1 transmission-line output power combiner. The amplifier has 20.5 dBm peak saturated output power with 20.8% PAE and 15dB associated large-signal gain at 140GHz. At 1dB gain compression, the output power is 17dBm with 9.7% PAE. The amplifier's peak small-signal gain is 20.3dB at 140GHz, and the small-signal 3-dB bandwidth is 120-163GHz. Over a 125-150GHz bandwidth, the saturated output power is within 2dB of its 140GHz maximum, with an associated PAE greater than 14.3%. The amplifier consumes 0.52W DC power and occupies 0.69mm
²
area. To the authors' knowledge, this result improves the state-of-the-art peak PAE at 140GHz by 1.6:1 for amplifiers of comparable saturated output power.