In a major scientific breakthrough, researchers have developed a new technology that allows small electronic devices to get power from Wi-Fi and Bluetooth signals in the air. This means that in the future, some devices may no longer need traditional batteries. Instead, they will use energy from wireless signals around them.
The key to this invention is a special type of antenna called a rectenna—short for “rectifying antenna.” This rectenna can capture weak electromagnetic waves from Wi-Fi, 4G, 5G, and Bluetooth signals and turn them into electricity. The electricity produced is small, but it is enough to power low-energy devices like sensors, small electronics, and Internet of Things (IoT) devices.
At the heart of this technology is a scientific field called spintronics, which studies the behavior of tiny particles called electrons. Normally, electricity is created when electrons move, but spintronics focuses on how the electrons spin and interact with magnetic fields. Scientists have used this knowledge to design a nanoscale device called a spin rectifier, which is built from a material known as a magnetic tunnel junction.
This spin rectifier is extremely sensitive and can extract energy from radio frequency (RF) signals, which include the signals used by Wi-Fi and mobile networks. Because Wi-Fi is everywhere in modern society, this means energy can be collected almost anywhere—whether in homes, offices, or public spaces.
The system works by capturing the RF signals through a rectenna, converting them into a small amount of electricity, and then storing or directly using that electricity to power a device.
Scientists have already tested this technology successfully. In one experiment, they used it to power a commercial thermometer, showing that small electronic devices can function without needing a traditional battery.
The biggest potential for this technology is in Internet of Things (IoT) devices. IoT devices are small gadgets that connect to the internet and are used in smart homes, health monitoring, security systems, and industrial automation. Many IoT devices require very little energy to function, so using rectennas to power them could reduce the need for disposable batteries, making technology more sustainable and environmentally friendly.
In 2019, researchers from MIT and the Technical University of Madrid developed a flexible rectenna made from a special material called molybdenum disulfide (MoS₂). This rectenna was able to convert Wi-Fi signals into about 40 microwatts of electricity—enough to power small sensors or medical devices like heart monitors.
This new technology has the potential to revolutionize the way we power small electronics. Imagine smartwatches, medical implants, or wireless sensors working without ever needing to be charged.
However, there are still challenges to overcome. Right now, the amount of energy harvested is quite small. Scientists are working on improving the efficiency of rectennas so they can generate more power. They are also exploring how to integrate this technology into more devices, from smartphones to wireless earbuds.
If successful, this invention could reduce the world’s dependence on disposable batteries, which are harmful to the environment. It could also make electronic devices more convenient, removing the need for constant charging.
In the future, we may see a world where small electronics are powered simply by the Wi-Fi signals that already exist all around us.
