A NOVEL MONOLITHIC LNA INTEGRATING A COMMON-SOURCE HEMT WITH AN HBT DARLINGTON AMPLIFIER

Here we report on the results of a novel HEMT-HBT LNA MMIC fabricated using selective molecular beam epitaxy (MBE) techniques. This unique circuit monolithically integrates a low-noise common-source HEMT with an HBT Darlington feedback amplifier to achieve high gain, low noise figure, and nide bandwidth utilizing a compact direct-coupled topology, The miniature direct-coupled MMIC is 0.9 x 0.7 mm(2) in size and obtains 1-8 GHz bandwidth, greater than 17.5 dB gain, and a minimum noise figure of 2.5 dB, The maximum IP3 is 18 dBm with a saturated output power (P-sat) > 12 dBm, The HEMT-HBT amplifier achieves comparable P-sat performance to the conventional HBT only Darlington amplifier while achieving over 2-dB reduction-in noise figure across the band, This work benchmarks the first HEMT-HBT MMIC that illustrates microwave performance advantages when compared to an HBT-only design.