This Measurement Guide provides instructions for using the 3744A-Rx mmWave Receiver Module for making noise figure measurements.

VectorStar Noise Figure Option 41 and Differential Noise Figure Option 48 provide noise figure measurements for frequencies from 70 kHz to 70 GHz using the standard VNA platform. Options 41 and 48 use the cold-source method using terminations and absolute power measurements instead of hot/cold noise sources. The cold-source noise figure measurement removes the errors associated with mismatch differences between the hot and cold states of the noise source and simplifies calibration and traceability. Using the cold-source method provides traceability paths through the power sensor and is readily available compared to the calibration requirements of the noise source. The result is a simple, accurate method of noise figure measurements up to 70 GHz when using the VectorStar MS464X platform.

Measuring noise figure above 70 GHz (in mmWave waveguide bands) in the past resulted in complex configuration of mmWave receivers and multiple paths of traceability. Often the use of spectrum analyzers and mmWave mixers were required. The result is time consuming system setups with minimal traceable paths to a standards laboratory and often with less than optimum uncertainties. mmWave VNAs were often not used since the mmWave modules used for the upper frequency bands did not provide a receiver with optimum noise figure. The 3744A-Rx mmWave receiver (based on the 3743A mm‑Wave module) provides the noise figure performance required and now makes possible true mmWave noise figure measurements, taking advantage of the accuracy and ease of use of the VectorStar VNA.