Wind, solar, fossil fuels: these are all familiar energy sources. But Wi-Fi? Few people know that it, too, can generate electricity.
The trick? Converting electromagnetic waves into direct current using an emerging technology. A new energy revolution may be on the horizon.
Researchers are exploring "rectennas," or rectifying antennas, capable of converting radio frequency waves into usable energy. These devices capture Wi-Fi, Bluetooth, and radio signals surrounding us, though they still face challenges with conversion efficiency.
A group of scientists from Singapore, Japan, and Italy has developed a more efficient rectenna. Their technology harvests ambient signals and converts them into continuous energy. This device can power small electronic devices. The researchers employed an innovative approach: spintronics. By manipulating the spin of electrons in magnetic materials, they successfully extracted energy from ambient signals and transformed it into electric current.
For now, this technology remains in the prototype phase. However, initial results are promising. The researchers are considering integrating a rectifying antenna on a chip to further improve efficiency and miniaturization. This discovery opens up exciting prospects for the future of connected devices and sensor networks. Fewer batteries, less energy consumption, and a lower environmental impact: these are the potential benefits of this groundbreaking technology.
The conversion of radio waves into electricity could even become a green and autonomous alternative. Eventually, this technology might enable continuous energy generation effortlessly, simply from the waves present around us. The era of devices powered by ambient waves may be closer than we think. If researchers succeed in perfecting this technology, it could well revolutionize our daily lives.
What is a rectifying antenna?
A rectifying antenna, often referred to as a rectenna, is a device designed to convert electromagnetic waves, such as those emitted by Wi-Fi or Bluetooth, into electricity. It captures these waves via an antenna, which transforms them into alternating current. This current is then rectified into direct current through a rectifying circuit.
Rectennas consist of an antenna, often a dipole type, and a diode. This diode is crucial for rectifying the alternating current—that is, transforming the oscillating current into a continuous flow of electricity that can be used to power small devices. The efficiency of rectennas depends on minimizing energy losses during this conversion process.
How does energy conversion in rectennas work?
The working principle of a rectenna is based on inducing current through the captured electromagnetic waves. When these waves hit the dipole antenna, they generate an alternating current. The diode connected to the antenna then plays a crucial role by rectifying this current, converting alternating current into direct current.
However, this process is complex and subject to energy losses, particularly in traditional rectennas. New research aims to improve the efficiency of these devices, particularly by using nanomaterials or innovative technologies like spin rectification, to maximize conversion and potentially power devices using ambient radio frequency signals.
Article by: Cédric DEPOND