GaAs HBT MMIC broadband amplifiers from DC to 20 GHz

Abstract

Three monolithic wideband and high-gain amplifiers implemented with 2-3- mu m GaAs heterojunction bipolar transistor (HBT) monolithic microwave IC (MMIC) technology are presented. A single-stage direct-coupled amplifier achieves a 3-dB bandwidth from DC to 20 GHz, which is believed to be the widest bandwidth reported for direct-coupled amplifiers. The amplifier has a 6-dB nominal gain with a peak gain of 7.3 dB at 10 GHz. The 1-dB compression is 10 dBm at midband, and the noise figure is between 7 and 10 dB over the bandwidth. A two-stage version of this amplifier achieves 14.5-dB gain up to 12 GHz. Its output power and noise performance are comparable to the single-stage version. The third wideband amplifier design is based on passive component and microstrip matching circuitry. The matched amplifier has 14.5-dB nominal gain with a 3-dB bandwidth from 5 to 12 GHz.<>