Kw. Kobayashi et al., A NOVEL MONOLITHIC LNA INTEGRATING A COMMON-SOURCE HEMT WITH AN HBT DARLINGTON AMPLIFIER, IEEE microwave and guided wave letters, 5(12), 1995, pp. 442-444
Here we report on the results of a novel HEMT-HBT LNA MMIC fabricated
using selective molecular beam epitaxy (MBE) techniques. This unique c
ircuit monolithically integrates a low-noise common-source HEMT with a
n HBT Darlington feedback amplifier to achieve high gain, low noise fi
gure, 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 obtai
ns 1-8 GHz bandwidth, greater than 17.5 dB gain, and a minimum noise f
igure of 2.5 dB, The maximum IP3 is 18 dBm with a saturated output pow
er (P-sat) > 12 dBm, The HEMT-HBT amplifier achieves comparable P-sat
performance to the conventional HBT only Darlington amplifier while ac
hieving over 2-dB reduction-in noise figure across the band, This work
benchmarks the first HEMT-HBT MMIC that illustrates microwave perform
ance advantages when compared to an HBT-only design.