On 24 September 2024, NSTIC (GaN) had the honour of hosting Professor Akio Wakejima from Kumamoto University for an engaging seminar on the latest breakthroughs in GaN HEMT (Gallium Nitride High Electron Mobility Transistor) technology. The event brought together professionals and researchers eager to explore how GaN semiconductors are transforming power conversion, microwave wireless power transfer, and thermal management systems.

Advancing Wireless Power Transfer with GaN HEMT

During his presentation, Professor Wakejima shared pioneering work on the Gated-Anode Diode using AlGaN/GaN HEMT, which plays a key role in rectification for microwave wireless power transfer. One of the major highlights was achieving 90% power conversion efficiency, a remarkable feat made possible through GaN HEMT technology.

This innovation, developed in collaboration with JAXA, represents a major leap forward in wireless power transfer applications, particularly for space-based projects such as the Luna mission. By demonstrating such efficiency, Professor Wakejima’s work showcases the real-world potential of GaN-based systems in powering next-generation communications and aerospace technologies.

Innovations in Thermal Management

Beyond efficiency, Professor Wakejima addressed one of the most critical challenges in high-power GaN HEMT devices — thermal management. He presented an innovative approach using graphite carbon, which significantly improves heat dissipation and enhances device reliability.

Effective thermal solutions are essential to unlocking GaN’s full potential, especially for high-frequency and high-power systems. These insights are particularly relevant as industries continue to demand compact, efficient, and durable semiconductor devices.

Driving the Future of Power Electronics

The seminar offered participants valuable insights into how wide bandgap semiconductors like GaN are shaping the future of power electronics and wireless technology. By integrating materials innovation with engineering design, Professor Wakejima’s research is paving the way for scalable, energy-efficient systems that support next-generation communication and energy infrastructures.

About the Speaker

Professor Akio Wakejima received his B.E. and M.E. in Material Physics, and his Ph.D. in Electrical Engineering from Osaka University, Japan, in 1992, 1994, and 2007 respectively. From 1994 to 2010, he worked at the Nano-Electronics Research Laboratories (formerly Kansai Electronics Research Laboratories) at NEC Corporation, focusing on III-V compound semiconductor devices for communication and radar applications.

In 2003, he expanded his research at the Georgia Institute of Technology in the United States. Since 2010, he has served at the Nagoya Institute of Technology, and in 2024, he joined Kumamoto University, where his current research focuses on GaN-based HEMTs for microwave and millimetre-wave power amplifiers and rectifiers.

He is also a member of IEICE, a senior member of IEEE, and currently serves as Vice Chair of the IEICE Technical Committee on WPT and Chair of the IEEE MTT-S Nagoya Chapter.

Conclusion

Professor Wakejima’s seminar highlighted how GaN HEMT technology continues to redefine the limits of efficiency, performance, and reliability in modern electronics. From achieving record-setting power conversion efficiency to tackling thermal challenges through advanced materials, his work demonstrates how GaN can power a new generation of sustainable, high-performance applications in wireless communications, power conversion, and space systems.

NSTIC (GaN) extends its appreciation to Professor Akio Wakejima for sharing his expertise and inspiring discussions that continue to advance the global GaN semiconductor community.