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 0.18-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 micro-mixer with 19-dB conversion gain and IPldB = -20 dBm and IIP3 = -13 dBm when RF = 2.4 CHz 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.
- Deep N-well