An Ultra-Wideband High-Linearity CMOS Mixer With New Wideband Active Baluns

A 2-11-GHz high linearity CMOS down-conversion mixer with wideband active baluns using 0.18-mum CMOS technology is demonstrated in this paper. The mixer employs a folded cascode Gilbert cell topology and on-chip broadband active baluns. The folded cascode approach is adopted to increase the output swing, and the linearity is enhanced by a harmonic distortion canceling technique derived from the harmonic balance analysis. The proposed configuration shows the highest IIP₃ and IP_{1 dB}, and exhibits more compact size than most published studies. A broadband active balun is used to generate wideband differential signals, together with the derivation of a closed-form expression for the phase imbalance. This single-ended wideband mixer has the conversion gain of 6.9plusmn1.5 dB, input 1-dB compression point (IP_{1 dB}) of - 3.5 dBm, single-sideband noise figure of 15.5 dB, and third-order input intercept point (IIP₃) of 6.5 dBm under the power consumption of 25.7 mW from a 1.8-V power supply. The chip area is 0.85 x 0.57 mm².