A 0.18- m CMOS CMFB DOWNCONVERSION MICROMIXER WITH DEEP N-WELL TECHNOLOGY FOR LO-RF AND LO-IF ISOLATION IMPROVEMENTS

CMOS deep N-well technology can eliminate the physical effects of NMOS transistors and reduce substrate noise and coupling in order to reach the NMOS channel. These properties result in better LO-IF and LO-RF isolations in a Gilbert micromixer. Two identical 0.18m CMOS downconversion micromixers (except at the RF input stage) with deep N-well or without deep N-well are fabricated in adjacent areas of the same wafer for the purpose of isolation comparison. A 37-dB LO-IF and 38-dB LO-RF isolation downconversion micromixer with 19-dB conversion gain and IP1dB 20 dBm and IIP3 13 dBm when RF 2.4 GHz and LO 2.25 GHz is demonstrated here using 0.18m-deep N-well CMOS technology. On the other hand, a downconversion micromixer without deep N-well has almost identical power performance but achieves only 20-dB LO-IF isolation and 21-dB LO-RF isolation. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 168–170, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20759