A 5.2 GHz 47 dB Image Rejection Double Quadrature Gilbert Downconverter Using 0.35 µm SiGe HBT Technology

Tzung-Han WU
Chinchun MENG
Tse-Hung WU

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E90-A    No.2    pp.401-405
Publication Date: 2007/02/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e90-a.2.401
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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A 5.2 GHz 1 dB conversion gain, IP1 dB = -19 dBm and IIP3= -9 dBm double quadrature Gilbert downconversion mixer with polyphase filters is demonstrated by using 0.35 µm SiGe HBT technology. The image rejection ratio is better than 47 dB when LO=5.17 GHz and IF is in the range of 15 MHz to 45 MHz. The Gilbert downconverter has four-stage RC-CR IF polyphase filters for the image rejection. Polyphase filters are also used to generate LO and RF quadrature signals around 5 GHz in the double quadrature downconverter.