V-band monolithic two stage HEMT amplifiers

Two different types of HEMT (high-electron-mobility transistor) monolithic low-noise amplifiers (LNAs) using AlGaAs/GaAs and pseudomorphic InGaAs/GaAs materials have been developed and have demonstrated excellent performance at 60 GHz. These monolithic LNAs have achieved noise figures of 5 dB, as well as associated gains of 11 dB. These two-stage circuits both utilize 0.2×60-μm HEMT devices for both bandpass and low-pass circuit topologies. Noise figures as low as 4.5 dB have been observed for single-stage MMIC- (monolithic-microwave-integrated-circuit) implemented LNAs, and gains in excess of 20 dB have been observed for three-stage versions of this amplifier with a 5-dB noise figure in the V band. This result represents the state-of-the-art monolithic HEMT amplifier performance for AlGaAs and pseudomorphic InGaAs materials. This MMIC amplifier can occupy about less than one-third the size of existing MIC hybrid V -band LNAs. This represents a significant size reduction and cost saving due to repeatable circuit performance with monolithic technology. The chip sizes are both 1.6×2.7 mm for these two-stage amplifiers