A new 5‐GHz CMOS MMIC for down conversion with an active balun and current‐folded mixer

A new 5‐GHz CMOS MMIC for a down‐conversion structure with an active balun and current‐folded mixer is proposed for improving linearity, LO‐to‐RF isolation, and conversion gain with low voltage supply. It features a current‐folded mirror with a source‐degeneration active balun, thus avoiding the need for an extra transformer balun and amplifier for the RF signal. The proposed new CMOS mixer is implemented using a CMOS 0.18‐μm standard process and 40 mA from a 1.8‐V voltage supply. The measured results show that the conversion gain and IP 1dB are more than 3.7 dB and −6.5 dBm, respectively. Furthermore, the mixer exhibits good performances on IIP 3 and LO‐to‐RF isolation with 12 dBm and 43 dB, respectively. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 206–209, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21124