Best Practice for On-Wafer Millimeter Wave Noise Figure Measurements

Equations are developed for convenient, but rigorous, corrections to on-wafer noise figure measurements based on the radiometer equation. The suitability of the approach for millimeter-wave measurements is demonstrated by presenting measured results for a W-Band (75-110GHz) MMIC low-noise amplifier (LNA). The measured quantities are vector-corrected to specified measurement planes by processing received noise temperatures (or noise power) and applying the developed equations to the measured system characteristics, such as probe S-parameters and noise source reflection coefficients. This technique provides a more rigorous treatment of the losses and mismatches present in a measurement system, yielding more accurate noise figure results compared to those obtained using scalar-corrected quantities. The results for the selected LNA show the noise figure to be on the order of 4 dB over 93-95 GHz, with an average discrepancy of 0.7 dB between noise figure corrections using only scalar loss information and the rigorous noise figure corrections based on vector S-parameter corrections presented here.