Accurate analysis of RF noise characteristics in active MOSFET Mixers in 90 nm technology

In this paper an accurate noise analysis for active mixers in 90 nm technology, based on the variations of the two parameters W/L (transistor size) and f_LO (local oscillator frequency) is presented. The contribution of the gate resistance noise to the gate and drain total current noises is considered, whereas this noise is usually assumed to be an independent source in the literature. It is shown that the variations of the noise generated by the switching pair in a mixer due to W/L variations in a wide range of local oscillator frequency, is less than the variations of the noise generated by the transconductor section of the mixer, which this matter shows the importance of the transconductor. Also it is shown that for the gate-source voltage values near to the threshold voltage value, the variations of the noise generated by the switching pair and the transconductor due to W/L variations, is reduced. In this middle, the reduction of the noise generated by the switching pair is more.