A high-efficiency HBT MMIC power amplifier

An AlGaAs/GaAs heterojunction bipolar transistor monolithic microwave IC (HBT MMIC) power amplifier is developed that demonstrates very high power-added efficiency, high gain, and broad bandwidth. It uses a cascode structure with four 200- mu m common-emitter HBT cells driving four common-base cells of the same size. This amplifier achieves over 14-dB gain from 6 to 10 GHz, with a peak power-added efficiency (PAE) of 47% at 7.5 GHz at an output power level of 31 dBm. This corresponds to a power density of over 3 W per millimeter of emitter length. Input and output matching networks, as well as biasing networks, are all contained within the chip, which measures 80*80 mils (2*2 mm).<>