ABSTRACT
This paper describes 950MHz power performance of a double-doped AlGaAs/ InGaAs/AlGaAs heterojunction FET(HJFET) operated at a single low bias voltage. The developed 1.0 μ m gate-length HJFET exhibited a maximum drain current of 300mA/mm, a transconductance of 240mS/mm, a gate-to-drain breakdown voltage of 13V and a threshold voltage of -0.35V. Operated with a single 3.0V DC bias supply, a 21mm gate periphery HJFET, tuned for maximum power-added efficiency(PAE), showed 1.45W saturated output power and 80.4% maximum PAE. When the device was tuned for minimum adjacent channel leakage power at 50kHz off-center frequency(Padj), a π /4-shifted QPSK output signal of 2.45W was demonstrated with 47.1% PAE and -50.6dBc Padj under a single 3.0V bias operation. The developed HJFET is promising for personal digital cellular power modules operated with a single low-voltage supply.
