21 GHz highly efficient composite-channel InP HEMT

State-of-the-art power performance was demonstrated from the composite-channel InP HEMT by on wafer load-pull measurements at 21 GHz. At a drain bias of 3 V, an 8-finger 500-/spl mu/m device delivered 23 dBm or 400 mW/mm of output power with 66% power-added efficiency and 10.5 dB associated gain. The linear gain was 16.9 dB. An output power of 24.5 dBm or 560 mW/mm with 60% power-added efficiency and 10 dB associated gain was achieved at 3.5 V drain bias.