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

摘要

A 5.2 GHz 1 dB conversion gain, IP_(1dB) = -19 dBm and IIP_3= -9 dBm double quadrature Gilbert downconversion mixer with polyphase filters is demonstrated by using 0.35μm 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.