In the early 1900s, Nikola Tesla envisioned a structure that could deliver power through air, without connectors. The Wardenclyffe Tower, also known as the Tesla Tower, became a lost dream when its investment dwindled. Associate Professor Matt Reynolds and his team at Intellectual Ventures are developing novel approaches to wireless power transmissions that make this power possible and profitable.
The novel approach involves metamaterials. This technology has gained attention by offering real-world legitimacy to Harry Potter’s “invisibility cloak.” Simply, metamaterials are a class of material engineered to produce properties that don’t occur naturally. For wizard enthusiasts, some metamaterials can bend electromagnetic radiation (e.g. light) around an object, giving the appearance that it isn’t there at all.
For Reynolds and his team, these materials allow about 8 watts’ worth of microwaves to be beamed across a lab space, lighting up an array of LED lights by shooting microwaves at a metamaterials-based reflective array. This array is about the size of a chalkboard, allowing the microwaves to focus on their intended target.
The researchers expect to scale up the system to power devices at distances of 160 feet (the width of a football field) or more. By increasing the range, they will be able to apply the technology to drone flight. On average, free-flying drones are limited to 20 minutes of flight time. If you could beam enough power to keep them in the air, they could hover indefinitely. This proves a useful feature for individuals who use drones to monitor security perimeters, inspect infrastructure ranging from railways to cellphone towers or produce aerial video footage.
This past fall, Reynolds and collaborators released new research on the development of a wireless charging hub. The new system involving metamaterials could be adapted to create wall panels capable for home charging. Reynolds said today’s wireless charging systems tend to take advantage of electromagnetic induction, which only works over a short range. An example of this would be an electric toothbrush. The toothbrush sits on a charging stand, which produces a proximal interaction.
“In order to get longer-range wireless power, you need to use fundamentally different physics,” Reynolds said in a recent article.
This fundamentally different physics, ushered in through metamaterials, has distinct advantages over similar wireless power systems, such as laser-beamed power systems or induction stations. The microwave beam can be focused and redirected with relatively high efficiency and with no moving parts.
Currently, the team is looking at high-end and large-scale applications. However, if researchers can operate the system at higher frequencies in the future, that could encourage the development of smaller devices that cost less and are capable of beaming out more power.