1.9GHz band highly linear 2-stage power amplifier MMIC based on InGaP/GaAs HBT

This paper describes a highly linear two-stage power amplifier monolithic microwave integrated circuit (MMIC) for the 1.9 GHz band based on InGaP/GaAs hetero-junction bipolar transistor (HBT). For achieving the highly linear power amplifier, the active biasing circuits have been optimized for the 1^st- and 2^nd-stages´ third-order intermodulation distortion products (IMD3s) by cancelling them each other. Based on the optimized circuit parameters, the two-stage power amplifier MMIC has been designed and fabricated to verify the cancellation effect over the 1.9 GHz band. The fabricated MMIC exhibits a high third-order intercept point (OIP3) of 48 dBm at an output power of 25 dBm, an output power at 1 dB compression point (P1dB) of 30 dBm, a high PAE of 35.8% at P1dB, and a gain of 28.5 dB under a supply voltage of 5 V and a quiescent current of 345 mA.