• home_icon HOME
  • Research
  • Highlights
Transfer technology for more independent and active movement of intelligent objects

Wireless Power Transfer (WPT) is a technology that transfers energy without a transmission line by converting electrical energy into a specific frequency electrical signal or light wave in the form of an electromagnetic wave. As a base technology required for the independent, active movement of intelligent objects employed by smart homes, smart factories, autonomous vehicles and artificial intelligence technologies, WPT will become a game changer in the industry including smart devices and IoT. A research team led by Professor Ju Yong Lee has successfully developed a WPT system that allows for the transmission of information and electricity simultaneously using the same resources based on a multiple-antenna system. By establishing an integrated PoC system for charging and wireless power transmission with high transmission/reception efficiency, it is expected to lead to more effective system modularization and improvement of efficiency.

Higher efficiency achieved with development of WPT system for simultaneous transmission of information and power

WPT technology is categorized into magnetic induction/magnetic resonance method, radio frequency (RF) method, infrared light method and ultrasonic wave method. △For the magnetic induction/resonance method, the transmission distance is relatively short and the terminal can be charged only when it is in the correct contact location. △The RF method transmits/receives electromagnetic waves, enabling long-distance transmission. An array antenna is used for higher efficiency, but a bigger size antenna is required at low frequencies. △The infrared method utilizes a laser. △The ultrasonic method converts energy from a transmitter into ultrasonic waves and transmits those, and the received ultrasonic waves are changed back to electrical energy.

Prof. Lee and his team developed a WPT system that allows for the transmission of information and electricity simultaneously using the same multiple-antenna based resources. The initial goal was to achieve 50% efficiency at a distance of 10m, but it was unrealistic when first simulated. They heightened the
frequencies, and then the desired energy efficiency was achieved, which led to the development of a prototype. They continued the study to achieve a level of efficiency in which all factors for transmission and reception were satisfied via the use of energy-efficient elements. The team also developed a high-efficiency transmission RF module that supports a waveguide array-based transmit antenna and a power amplifier (PA). The team built an integrated PoC system for wireless power transmission and charging by making a “Rectenna” (Receiving antenna + Rectifier) with high-density receiver and DC-DC converter module; using the system, they achieved 50% efficiency between receiving and transmitting antennas and 70% efficiency at the receiving rectifier, using a 10m transmission/reception distance, and compact-sized transmission (60cmx60cm) and receiving (30cmx30cm) antennas.

“We will develop the optimal technology, keeping in mind any possible harm to human body”

Prof. Lee said, “Wireless power transmission technology must ensure human harmlessness, as well as considerations for efficiency, modularization, and economic feasibility until a prototype is finally commercialzed.” He continued, “For this technology to be successfully commercialized, we must obtain
desired results through accurate predictions and simulations in the process of developing source technologies; consistent investment and research is also required.”

Research Prof. Ju Yong Lee
2020 KI Annual Report

KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (34141)
T : +82-42-350-2381~2384
F : +82-42-350-2080
Copyright (C) 2015. KAIST Institute