A WIDE-BAND HEMT CASCODE LOW-NOISE AMPLIFIER WITH HBT BIAS REGULATION

We have achieved broadband low-noise performance and dc bias regulatio n in a single compact HEMT-HBT MMIC. The self-biased MMIC achieves gre ater than 13 dB gain from 1-8 GHz with a noise figure of less than 1.9 dB across the band and a minimum noise figure of 1.6 dB, The MMIC con sists of a HEMT cascode first stage and a source-follower output stage , with shunt feedback between the stages to obtain good broadband nois e figure and gain performance. Bias regulation is realized by monolith ically integrating an HBT current regulator with the HEMT LNA using se lective MBE. This is the first microwave demonstration of key monolith ic HEMT-HBT circuit functionality combined with state-of-the-art low-n oise figure performance, realized in a miniature 0.9 x 1.0 mm(2) MMIC.