DESIGN OF 900 MHZ SIGE POWER AMPLIFIER WITH LINEARIZATION BIAS CIRCUIT

A single stage 900MHz power amplifier (PA) with linearization bias circuit is designed with HHNEC 0.5μm BIS500G power SiGe BiCMOS process. It is implemented by single-ended common emitter structure as a class AB power amplifier. The adopted active bias circuit is originally explained by using two virtue current sources, so that the mechanism of the improvement of linearity can be described more clearly. Then the mechanism is applied to guide the design of a power amplifier with an active bias circuit, which shows better linearity than resistor biased power amplifier by simulation. Through further design and measurement, the fabricated single stage power amplifier exhibits output power 1 dB compression point (OP1dB) of 18.9 dBm, with power added efficiency (PAE) of 26.75% and power gain of 20.9 dB under 3.3V voltage supply.