Temperature compensating bias circuit for GaAs HBT RF power amplifiers with stage bypass architecture

The design of a temperature compensating bias circuit applicable to GaAs HBT radio frequency (RF) power amplifiers (PAs) is presented. It is developed by adding a simple voltage-compensation circuit to the existing base bias circuit. It is applied to a stage bypass RF PA and the experimental results show that the quiescent current (Q-current) remains nearly unchanged over a temperature range between -30-85degC, which markedly improves the linearity of the PA at low temperatures.