The end of batteries and cables is getting closer: researchers from MIT and the Polytechnic University of Madrid have created a device that converts the WiFi signal into electricity.
A collaboration between MIT and the Polytechnic University of Madrid could bring us closer to the end of the cables that we spend so many hours unraveling or trying to hide. Researchers have developed a device that converts the WiFi signal into electricity, making wireless charging something more tangible.
It is a rectenna – from rectifying antenna – a type of antenna that is used to convert electromagnetic waves into direct current. The key is in the material they used to make the rectena. Instead of using silicon or gallium arsenide – used in current electronic devices – they used molybdenum disulfide. It is a nanomaterial with only three atoms of thickness, which gives it great flexibility, and also stands out for being a semiconductor. To this we must add that it is cheap to produce it.
The fact that the rectena is so flexible makes it the ideal device to be installed on all types of devices, from wearables, to smart watches and flexible smartphones.
Thus, it is also a relevant milestone for the health sector and could be used in implants and medical devices that could be swallowed. “Ideally, you do not want to use batteries to power these systems, because if there is a lithium leak, the patient could die,” explained Jesús Grajal of the Polytechnic University of Madrid.
The rectenna can capture and convert up to 10 GHz and at a much higher speed than other rectenas. Of course, at the moment it generates a small amount of electricity: it has produced around 40 microwatts when exposed to conventional WiFi signals, of around 150 microwatts. However, this would be enough to power an LED or silicon chips.
The researchers are also thinking on a large scale. “And if we could develop electronic systems that wrap around a bridge or cover an entire highway, or the walls of our office and bring electronic intelligence to everything that surrounds us, how do you produce energy for those devices?”, Said Tomás Palacios of MIT. “We have come up with a new way of feeding the electronic systems of the future – collecting WiFi energy so that it can be easily integrated into large areas – to bring intelligence to all the objects that surround us,” the engineer added.