Complete On-Wafer Noise-Figure Characterization of 60-GHz Differential Amplifiers

In this paper, we show that the differential noise figure of differential amplifiers is better measured directly by using baluns rather than be derived from single-ended measurements. For on-wafer measurements at 60 GHz, this can best be done using RF probes with integrated baluns. To extract the full 4 × 4 noise correlation matrix needed to predict the circuit behavior under any operating condition, this needs to be extended with at least one single-ended noise-figure measurement taken on an individual amplifier. For the experimental two-stage differential amplifier realized in 45-nm node CMOS studied in this paper, we found a noise figure of 3.2 dB. This is, to the best of our knowledge, the lowest noise figure reported at 60 GHz in any CMOS technology thus far.