A research group led by Professor Shunsuke Fukami of Tohoku University has developed a magnetic tunnel junction that transmits and receives radio waves in the 2.4 GHz band of Wi-Fi and its connection technology in collaboration with the National University of Singapore.We succeeded in charging the capacitor for 8 seconds with 5 elements connected in series and illuminating the LED for 1 minute.
With the progress of information and communication technology, the IoT (Internet of Things) society has arrived. In the IoT society, many information terminals are connected to the Internet via wireless LAN (Wi-Fi), but the energy of Wi-Fi radio waves that fly around us continues to be wasted.The use of the energy of this radio wave is considered as one of the power sources for energy harvesting.
Electrons have electrical properties (charges) and magnetic properties (spins), and spintronics is a discipline that aims for engineering use by using these two properties at the same time.This time, the research group has developed an important technology that can generate electricity from 2 GHz radio waves using a spintronics element called "magnetic tunnel junction".Using this technology, we constructed a simple demo system consisting of eight magnetic tunnel junctions connected in series, a capacitor, a boost converter, and an LED that emits light at 2.4V, and conducted a principle demonstration experiment of energy harvesting.It was confirmed that the capacitor was charged in 8 to 1.6 seconds by the power generation from the 2.4 GHz radio wave of the magnetic tunnel junction, and the LED continued to illuminate for 3 minute by releasing this charge.
This achievement is an important step toward establishing a technology to drive IoT information terminals by efficiently using the radio waves of Wi-Fi, which is the power that is "continuing to be thrown away" around us.By developing the technology developed this time, it is expected to realize a wireless battery-free edge information terminal that senses and processes information using the power of Wi-Fi radio waves.
Paper information:[Nature Communications] Electrically connected spin-torque oscillators for 2.4 GHz WiFi band transmission and energy harvesting
