Modern consumers use various devices for communication, including smartphones. 5G technology has been commercialized, and research on 6G has begun. Wireless charging is required to efficiently use smart devices, but currently available technology supports only distances up to a few centimeters, and energy harvesting-based IoT sensor power transmission is limited to mW units. Electromagnetic waves spread in all directions when traveling longer distances, and have poor efficiency at receiving units. Against this backdrop, the team led by Professor Ju Yong Lee developed a 10-meter wireless power transmission and charging technology via beamforming in millimeter-wave bandwidth, and succeeded in Watt-level power transmission for practical use.


Development of antenna and RF modules for wireless power transmission and charging

The proposed wireless power transmission and charging technology enables long-distance charging by sending electromagnetic waves in GHz frequencies. Electromagnetic waves usually spread in all directions when sent from base stations. Their efficiency decreases over longer travel distances as the amount received is significantly smaller. This study improved transmission efficiency by employing beamforming to focus electromagnetic waves towards the receiving unit. For long-distance wireless power transmission, a low complexity/high efficiency RF transmitter module and a high-efficiency wireless charging RF receiver module were developed. Electromagnetic waves were sent from a 60cm*60cm transmission antenna and received by a 30cm*30cm receiving antenna placed 10 meters away. By developing the world’s first prototype of a RF wireless power transmission system using millimeter waves, this study acquired core technology in wireless charging for the advancement of IoT smart devices and sensors.


Establishment of integrated PoC (Proof of Concept) system for wireless power transmission and charging

The team achieved a power transmission efficiency of 20% between transmission antennas using the integrated PoC system for wireless power transmission and charging. Most people avoid handling electrical devices due to the potential hazards posed by electromagnetic waves. The proposed integrated system for long-distance wireless power transmission and charging fundamentally reduces the risks of electromagnetic waves by activating a human avoidance algorithm when human presence is detected within a certain range of electromagnetic waves during transmission. In the age of IoT, in which smart devices communicate and exchange information with one another, the proposed technology will lay the foundation for wireless communications and power transmission.


Prof. Lee, Ju Yong
2019 KI Annual Report