4-GHz Inter-Stage-Matched SiGe HBT LNA with Gain Enhancement and No Noise Figure Degradation

Chinchun MENG  Jhin-Ci JHONG  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E90-A   No.2   pp.398-400
Publication Date: 2007/02/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e90-a.2.398
Print ISSN: 0916-8508
Type of Manuscript: Special Section LETTER (Special Section on Analog Circuit Techniques and Related Topics)
SiGe BiCMOS,  Gilbert mixer,  image rejection,  polyphase filter,  double quadrature downconverter,  

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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 µm SiGe HBT technology. This approach maintains the same current consumption because a low-pass π-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.