Experiment and analysis of microwave termination stability over temperature and time

A microwave termination is a single-port, 50 ohm device. We have developed experiments to determine the temperature stability on the VSWR performance of terminations. Measurements were made in a temperature and humidity chamber and by a vector network analyzer (VNA) outside the chamber. Accuracy of terminations will change with time. It is also desirable to understand the short-term stability and its implication towards the long-term drift. Empirical study shows a good agreement by using the modified linear regression technique.