Detailed investigation of active CMOS mixers noise in submicron technology

A unified noise figure expression incorporating the thermal noise and flicker noise has been proposed for active CMOS mixers. Based on the derived conversion functions with output resistance effect, the noise transforming factors for different stages are numerically computed to rigorously describe the noise output. The subthreshold conductance has also been taken into account by utilizing the latest continuous noise model and the simplified MOSFET I–V model. As a result, the frequency-dependent characteristic of noise expression is of competency for explaining the flicker noise mechanism, thus can be directly applied to active CMOS mixers with any IF characteristics. And good agreement is obtained between simulations and measurements.