4-GHz inter-stage-matched SiGe HBT LNA with gain enhancement and no noise figure degradation

Abstract

An effective way to boost power gain without noise figure degradation in a cascode low noise amplifier (LNA) is demonstrated at 4 GHz using 0.35 mu m SiGe HBT technology. This approach maintains the same current consumption because a low-pass pi-type LC matching network is inserted in the inter-stage of a conventional cascode LNA. 5 dB gain enhancement with no noise figure degradation at 4 GHz is observed in the SiGe HBT LNA with inter-stage matching.