2.4/5.7-GHz Dual-Band Dual-Conversion Low-IF Downconverter Using 0.35 mu m SiGe HBT Technology

Abstract

A 2.4/5.7-GHz dual-band dual-conversion low-IF downconverter is demonstrated using 0.35 mu m SiGe heterojunction bipolar transistor (HBT) technology. The first image signal is shifted away from the IF band by a complex Weaver architecture while the second image signal is eliminated by a complex Hartley architecture. The downconverter achieves a 45/44-dB image-rejection ratio of the first image (IRR1) and a 50/48-dB image-rejection ratio of the second image (IRR2) for 2.4/5.7-GHz modes, respectively, when IF frequency ranges from 20 to 40 MHz.