Using Commercial Source Measure Units for Traceable RF Power Measurements

As a National Metrology Institute (NMI), the National Institute of Standards and Technology (NIST) maintains traceable measurement capabilities for a variety of quantities, including microwave power. At NMIs and calibration laboratories, traceable microwave power measurements often rely on the principle of dc substitution. This approach involves a power meter that provides de power to a sensor under test. Typically, dc substitution power meters are implemented by analog electronics, making them difficult to maintain. Here, we explore programmable source measure units as an alternative implementation of the power meter. We offer a preliminary uncertainty analysis and describe a method to reduce measurement uncertainty due to the accuracy of the measurement equipment.