This paper describes 1.0 V operation power performance of a double doped AlGaAs/InGaAs/AlGaAs heterojunction FET for personal digital cellular phones. The developed FET with a multilayer cap consisting of a highly Si-doped GaAs, an undoped GaAs and a highly Si-doped AlGaAs exhibited an on-resistance of 1.3 Ωmm and a maximum drain current of 620 mA/mm. A 28 mm gate-width device, operating with a drain bias voltage of 1.0 V, demonstrated an output power of 1.0 W, a power-added efficiency of 59% and an associated gain of 13.7 dB at an adjacent channel leakage power at 50 kHz off-center frequency of -48 dBc with a 950 MHz π/4-shifted quadrature phase shift keying signal.