Characterization and Modeling of Dynamic Thermal Coupling in GaN MMIC Power Amplifiers

Paper i proceeding, 2024

The dynamic thermal coupling in integrated GaN power amplifiers is studied based on transient measurements on an amplifier structure with integrated temperature sensors. The results show that the thermal coupling from a transistor can modulate neighboring transistors with a low pass filtered response. Here, the cut-off frequency and amplitude of the modulation effect are reduced with separation while the phase shift increases. When applied to a large power amplifier, it is shown that the temperature gradient over the amplifier will vary dynamically, where five distinct time regions are identified. A numerical model is presented to validate the measurements. The results can be used to improve the accuracy of electro-thermal models of GaN power amplifiers.