An X band InGaP/GaAs HBT single stage MMIC power amplifier is reported.The self-aligning InGaP/GaAs HBT process was used to fabricate the circuit.The PA circuit is biased at the class AB state.The small signal S parameter test shows that at 8~8.5GHz,the linear power gain is 8~9dB,VSWRin<2,and VSWRout<3.After optimizing the collector bias,the linear gain is improved to 9~10dB.Under an 8.5GHz CW signal power test with optimized loading conditions,the P1dB of the circuit is 29.4dBm,relevant power gain is 7.2dB,and relevant PAE is 42%.The Psat of the circuit is 30dBm.
