A linearization technique for active mixers in zero-IF receivers with inherent balun

Abstract

A new technique with two different structures for linearization of active mixers in zero-IF receivers is presented. The proposed technique improves the IIP2 more than 20 dB by removing the transconductance common mode current at the mixer's output and IIP3 more than 5 dB in comparison with a basic Gilbert-cell mixer at equal conversion gain. Also, this technique allows us to use a singleended input in a fully differential structure without needing a bulky and noisy balun. These improvements are achieved at the cost of 0.8 dB increase in NF and also 0.6 mA more current dissipation in one structure.