Anaysis and design of linearity improved mixer using third-order transconductance cancellation

Abstract

This paper proposes a new linearity improvement technique using third-order transconductance cancellation. The proposed technique requires a transconductance stage composed of common-source and common-gate stages with source degeneration inductors and eliminates the third-order distortion term through a feed-forward compensation. The analysis of the proposed technique is performed using current equations representing nonlinear distortion. The proposed technique is applied to a CMOS RF mixer based on Gilbert cell. The simulated IIP3 of the proposed mixer is -2.5 dBm which is improved by approximately 7 dB compared with a conventional structure while consuming 4.14 mW from a supply voltage of 1.5 V.