50% high efficiency 1 W power heterojunction FET for 3.5 V CDMA cellular phones

This paper describes 950 MHz power performance of a double-doped AlGaAs/InGaAs/AlGaAs heterojunction FET (HJFET) operated at 3.5 V drain bias voltage (V_ds) for CDMA cellular phones. A 20 mm gate width HJFET delivered a power-added efficiency (PAE) of 50%, an output power of 1.0 W and an associated gain of 16.1 dB with an adjacent channel leakage power ratio (ACPR) of -42 dBc at 0.9 MHz off-center frequency. High efficiency performance was achieved over a wide range of an output power level by controlling a gate bias voltage. Even at a low V_ds of 2.0 V, PAE of 44% was achieved with 0.3 W output power and -42 dBc ACPR