A 0.18‐μm CMOS CMFB downconversion micromixer with deep N‐well technology for LO‐RF and LO‐IF isolation improvements

Abstract

AbstractCMOS 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 0.18‐μm 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 0.18‐μm‐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