THERMAL SCIENCE

International Scientific Journal

Ali Jebelli

,

Nafiseh Lotfi

,

Arezoo Mahabadi

,

Mustapha C.e Yagoub

SYSTEM-LEVEL THERMAL OPTIMIZATION OF FORCED-AIR COOLING FOR COMPACT HIGH-POWER ELECTRONIC SYSTEMS: APPLICATION TO A GAN MMIC AMPLIFIER

ABSTRACT
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.
KEYWORDS
thermal management, forced-air cooling, electronic cooling, heat transfer, conjugate heat transfer, numerical simulation, heat sink optimization, compact electronic systems, thermal design, cooling performance
PAPER SUBMITTED: 2026-04-04
PAPER REVISED: 2026-05-18
PAPER ACCEPTED: 2026-05-25
PUBLISHED ONLINE: 2026-06-20
DOI REFERENCE: https://doi.org/10.2298/TSCI260314080J
REFERENCES
[1] Mishra, U. K., et al., AlGaN/GaN HEMTs—An Overview of Device Operation and Applications, Proceedings of the IEEE, 90 (2002), 6, pp. 1022-1031
[2] Palacios, T., et al., High-Power AlGaN/GaN HEMTs for RF Applications, IEEE Transactions on Microwave Theory and Techniques, 53 (2005), 3, pp. 1250-1258
[3] Chowdhury, S., Mishra, U. K., Lateral and Vertical Transistors Using the AlGaN/GaN Heterostructure, IEEE Transactions on Electron Devices, 60 (2013), 10, pp. 3060-3066
[4] Sheppard, S. T., et al., High Thermal Conductivity Substrates for GaN Power Devices, IEEE Electron Device Letters, 30 (2009), 4, pp. 288-290
[5] Meneghini, M., et al., Reliability of GaN High-Electron-Mobility Transistors: State of the Art and Perspectives, IEEE Transactions on Device and Materials Reliability, 16 (2016), 3, pp. 525-544
[6] Timoshenkov, S. P., et al., Numerical Thermal Analysis of C-Band GaN Power Transistors under Pulsed Operation, Microelectronics Reliability, 100 (2019), 113392
[7] Chu, R. M., et al., Overview of Advanced Cooling Technologies for Power Electronics, Applied Thermal Engineering, 127 (2017), pp. 308-326
[8] Patil, A., Chavan, S., 3D Thermal Modeling and Optimization of High-Power IC Chips under Forced Convection, Thermal Science and Engineering Progress, 24 (2021), 100915
[9] Goyal, N., Kumar, M., Self-Healing Circuit Architecture for Thermal Reliability in 3D Integrated Systems, Microelectronics Reliability, 114 (2020), 113771
[10] Zhuo, R., et al., Microchannel Cooling Design for High-Frequency MMIC and Antenna Systems, Applied Thermal Engineering, 148 (2019), pp. 1061-1070
[11] Gupta, A., Kumar, V., Low-Temperature Co-Fired Ceramic Packaging for High-Frequency Microwave Applications, Journal of Electronic Packaging, 142 (2020), 3, 031004
[12] Sundaram, V., et al., Thermal-Performance Enhancement in Laminate and Glass Fan-Out Packaging for Power Amplifiers, IEEE Transactions on Components, Packaging and Manufacturing Technology, 11 (2021), 2, pp. 286-295
[13] Lee, Y., et al., Air-Cooled Metal Microchannels for High Heat-Flux Microelectronic Applications, International Journal of Heat and Mass Transfer, 184 (2022), 122274
[14] Pozar, D. M., Microwave Engineering, 4th ed., Wiley, Hoboken, NJ, USA
[15] Çengel, Y. A., Ghajar, A. J., Heat and Mass Transfer: Fundamentals and Applications, 5th ed., McGraw-Hill, New York, USA
[16] Versteeg, H. K., Malalasekera, W., An Introduction to Computational Fluid Dynamics: The Finite Volume Method, 2nd ed., Pearson Education, Harlow, UK
[17] Incropera, F. P., DeWitt, D. P., Fundamentals of Heat and Mass Transfer, 5th ed., Wiley, New York, USA
[18] ***, ANSYS Fluent Theory Guide, Release 2023, ANSYS Inc., Canonsburg, PA, USA
[19] Lasance, C. J. M., Ten Years of Boundary-Condition-Independent Compact Thermal Modeling of Electronic Parts: A Review, Heat Transfer Engineering, 29 (2008), 2, pp. 149-168
[20] Jebelli, A., et al., Enhancing Efficiency and Reliability in High-Power Microwave Amplifiers: A Novel Circuit Driver Approach, International Journal of Robotics and Automation, 14 (2025), 1, pp. 82-92
[21] Jebelli, A., et al., Advanced Thermal Management for High-Power ICs: Optimizing Heatsink and Airflow Design, Applied Sciences, 14 (2024), 20, pp. 1-14
[22] ***, QPA1010: 7.9-11.0 GHz 15 W GaN Power Amplifier Data Sheet, Rev. J, Qorvo Inc., Greensboro, NC, USA
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System-level thermal optimization of forced-air cooling for compact high-power electronic systems: Application to a GaN MMIC amplifier

© 2026 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International licence