High efficiency power HFETs for low power wireless applications [AlGaAs/InGaAs devices]

This paper discusses the development of depletion mode heterojunction FETs (HFETs) for high efficiency power amplifiers. At 850 MHz, a 12 mm HFET achieved power added efficiency of 72% and an output power of +31.5 dBm at V/sub ds/=3.0 V. An optimized HFET achieved 73% power added efficiency and 30 dBm output power at V/sub ds/=2.0 V. These devices also exhibited a 12 dB improvement in out-of-band noise performance compared to ion implanted MESFETs.