Second harmonic rejection based on feedback technique in CMOS mixer for multi-band DCR application

This paper presents a broadband linearization technique for CMOS Gilbert-based mixer in zero IF receivers. In the proposed mixer the second order distortion is reduced by using feedback technique in the RF transconductance stage. Creating a negative feedback loop is better suited for achieving broadband IIP2 improvement compared to other technique. Moreover, the added circuit increases the conversion gain of the mixer. Simulation results, using 0.13 μm CMOS TSMC model, show that the proposed technique improves IIP2 of more than 20 dB in the 900 MHz–6 GHz RF input frequency rang for 100 MHz output bandwidth in comparison with the conventional mixer. So this technique is suitable for multi-band DCR application. The total power consumption is 3.3 mW and the excess power consumption due to additional circuits used to implement cancellation mechanism is less than 1 mW.