Radiative wireless power transfer (WPT), which was known as microwave power transmission in the 20th century, is a technology that wirelessly transmits power via microwaves. In the 21st century, research and practical application of coupled wireless power transfer (WPT) using magnetic fields has progressed, and the research and development of microwave power transmission has also attracted attention, and in recent years it has come to be known as radiative wireless power transfer. Radiative WPT is a pioneering exploration of the academic field of wireless power transfer, marking the fourth electromagnetic wave application technology after communication, remote sensing, and heating. This academic field has significant ripple effects in both radio wave academia and industry.

The awardee began research and development of radiative WPT in the 1990s when he was a student. From the beginning to the present, he has been conducting research and development on Solar Power Satellites (SPS)(1), which wirelessly transmit power from a power plant in space orbit to the ground using microwave beams. Since 2009, he has served as the chairperson of the SPS research and development project that has been conducted by the Ministry of Economy, Trade and Industry for many years, leading SPS research and development(2) in Japan. He currently serves as the chairperson of the Space Solar Power Systems Society in Japan and as a member of the national space policy committee. Since 2000, he has been conducting research to advance the practical application of radiative WPT. From an early stage he has developed the wireless charging of electric vehicles using microwave beams, and in-room wireless charging of mobile phones called “ubiquitous power supply” (Fig. 1) and other demonstration experiments. He currently carries out research and development on simultaneous wireless information and power transfer using millimeter wave beamforming (Fig. 2)(3). In 2013, he established a consortium called WiPoT (Wireless Power Transfer Consortium for Practical Application) to accelerate all WPT businesses. As of 2024, WiPoT consists of 39 corporate members, 3 research institute members, and 56 academic members. WiPoT contributed to the revision of the domestic radio regulation ministerial ordinance for radiative WPT (920MHz, 2.4GHz, 5.7GHz)(4) in 2022, and the recommendation by ITU-R (International Telecommunication Union Radiocommunication Sector) in the same year(5).

The awardee has conducted many demonstration experiments of radiative WPT(6), demonstrating the usefulness of radiative WPT to the world, and succeeded in launching a new WPT industry. In addition, the awardee reviewed electromagnetic field theory from an energy perspective as differing from existing radio applications, returning to the basics of the academic field and popularizing new radio engineering(7). This research has been recognized around the world, including with the 2023 IEEE Journal of Microwaves Best Paper Award(8), the 2022 Electrical Science and Technology Promotion Association Minister of Education, Culture, Sports, Science and Technology Award, and the 2018 IEICE Communications Society Educational Achievement Award, etc. In the 12 years since 2012 when he became a professor, the supervised students in his laboratory have received 93 awards both domestically and internationally.

As mentioned above, the awardee has made significant contributions to the research and practical application of radiative WPT in the world and has created the foundation for Japan to continue to lead the world in this field. It has also become possible for children, who will be responsible for the future, to dream of “A world where electricity is available anytime and anywhere'” as a “Forecast of a future supported by information and communications 100 years from now”(9). The awardee has made significant achievements in the progress, research, and practical application of microwave technology as a new radio wave application, and is worthy of the Society's Achievement Award.

References

1. Naoki Shinohara (Editor and Author), “Solar Power Satellites (in Japanese)”, ISBN978-4-274-21233-8, Ohm-sha, 2012.7 (Chinese translation also available)
2. Naoki Shinohara, “R&D Project of Beam Microwave Power Transfer System toward Solar Power Satellites in Japan (in Japanese)”, IEICE Trans. C, Vol.J105-C, No.1, pp.11-18, 2022
3. Naoki Shinohara, Bo Yang, Wenyi Shao, Kenji Itoh, Naoki Sakai, and Naoki Hasegawa, “Novel Energy Harvesting and SWIPT System at 28 GHz with a Simple Phased Array”, Proc. IEEE International Conference on RFID Technology and Applications (RFID-TA2023), pp.209-212, 2023.9
4. Japan Coordinating Council for Wireless Power Transfer (JWPT) References (in Japanese) https://jwpt.jp/activities/
5. Recommendation to ITU-R SM.2151-0, 2022.9, https://www.itu.int/dms_pubrec/itu-r/rec/sm/R-REC-SM.2151-0-202209-I!!PDF-E.pdf
6. Naoki Shinohara, “Beam Control Technologies With a High-Efficiency Phased Array for Microwave Power Transmission in Japan”, Proceedings of the IEEE, vol.101, Issue 6, pp. 1448-1463, 2013
7. Naoki Shinohara, “Wireless Power Transfer via Radiowaves (Wave Series)”, ISTE Ltd. and John Wiley & Sons, Inc. States, 2014.1 (Chinese translation also available)
8. Christopher T. Rodenbeck, Paul I. Jaffe, Bernd H. Strassner II, Paul E. Hausgen, James O. McSpadden, Hooman Kazemi, Naoki Shinohara, Brian B. Tierney, Christopher B. DePuma, and Amanda P. Self, “Microwave and Millimeter Wave Power Beaming”, IEEE Journal of Microwaves, Vol.1, No.1, pp.229-259, 2021
9. Naoki Shinohara, “Progress of Research and Development of Wireless Power Transfer and Its Future (in Japanese)”, IEICE Magazine 1200th issue memorial special feature: ”Forecast of a future supported by information and communications 100 years from now”, 2024.3