Thermal characterisation of a pulsed power amplifier by direct channel temperature measurement

A technique is described that can be used to measure pulsed MESFET channel temperatures in active phased array systems. This measurement technique and the associated thermal model allows for accurate characterisation of instantaneous device channel temperature, and can be used in combination with RF measurement data to model temperature dependent phase and amplitude effects under various operating conditions. These models can then be used in waveform design to correct for thermally induced distortion of transmit waveforms.