System-level thermal optimization of forced-air cooling for compact high-power electronic systems: Application to a GaN MMIC amplifier

Efficient thermal management is essential in compact high-power electronic systems, where elevated operating temperatures can degrade performance and reduce operational reliability. This study presents a system-level thermal optimization of forced-air cooling for a compact high-power electronic amplifier with high thermal loading. The objective is to improve cooling effectiveness through the structured optimization of practical thermal management parameters without introducing a new cooling technology. A numerical methodology based on conjugate heat transfer simulations is used to evaluate the influence of fan performance, airflow orientation, enclosure airflow organization, and passive heat-sink integration under identical operating and geometric conditions. The thermal effect of each modification is examined sequentially to identify the most effective cooling configuration. The results show that airflow organization strongly influences thermal behavior, and that lateral airflow improves convective heat removal and temperature uniformity compared with the baseline vertical airflow configuration. The addition of a compact finned copper heat sink further enhances heat spreading and cooling performance. The best-performing investigated configuration reduces the maximum device surface temperature from approximately 50°C to 35°C under identical operating conditions. The proposed methodology provides practical design guidance for the thermal optimization of compact high-power electronic systems and can be extended to similar forced-air cooling applications.