Comparative analysis of methods for measuring thermal parameters of integrated microwave power amplifiers on bipolar transistors

A brief analysis of methods and features of measuring thermal parameters of integrated microwave power amplifiers on bipolar transistors (BT) is presented. The hardware and software complex implementing the method of measuring the thermal parameters of the amplifier according to OST 11 0944-96 and the original modulation method is described. In both methods, the temperature of the active region of BT crystals is determined by a change in a certain temperature-sensitive parameter (TSP) of BT when they are heated by pulsed power. The results of comparative measurements of the thermal resistance of the junction-housing of the L-band integrated microwave amplifier on silicon BT are presented. The optimal duration of the heating pulses in the standard method was determined based on the analysis of the previously measured transient thermal characteristics of the amplifier. To exclude the influence of transients when switching the amplifier from the heating mode to the measurement mode, the temperature of the BT crystal at the end of the heating power pulse was determined by interpolating the results of several TSP measurements under the assumption that the crystal cooling curve has a root character. It is shown that the results of measuring the thermal resistance of the junction-housing of an integral microwave amplifier by both methods are in good agreement with each other.