CMOS RF mixer no-linearity design

Design equations for the 1 dB compression point and 3rd-order intermodulation point as a function of circuit and technology parameters are derived using a Volterra series expansion. Linearity analysis for both single and double-balanced CMOS Gilbert mixers is examined. The transconductance stage using inductive degeneration is more linear than that using capacitive or resistive degeneration, and the single-balanced mixer is more linear than the double-balanced one at the same bias current and transconductance. The analytical predictions are verified with the Cadence SpectreRF circuit simulation and experimental data. Good agreement between the model predictions and experimental data is obtained.