Automatic, Calibrated and Accurate Measurement of S-Parameters in Climatic Chamber

When measuring RF or microwave devices under a temperature profile inside a climatic chamber, one of the main problems lies in the impossibility to have the network analyzer calibrated for all the temperatures measured along the profile. Typically, the calibration is performed just at room temperature, assuming that there is going to be an error in the rest of the measured temperatures. That error will be higher the further we are from room conditions. In this work, we present a systematic procedure for accurately measuring the S-parameters of a device at different temperatures. It applies a calibration algorithm using the S-parameters of the device under test (DUT) and of the calibration standards measured at the different temperatures of interest along the temperature profile.