‘Invisibility cloak’ is microwave wizard

A team led by scientists at

has demonstrated the first working ‘invisibility cloak’ that effectively render objects invisible to microwaves.

The cloak deflects microwave beams so they flow around a ‘hidden’ object inside with little distortion, making it appear almost as if nothing were there at all. It could have a variety of wireless communications or radar applications, according to the researchers.

They manufactured a two-dimensional version of the cloak using ‘metamaterials’ precisely arranged in a series of concentric circles that confer specific electromagnetic properties. Metamaterials are artificial composites that can be made to interact with electromagnetic waves in ways that natural materials cannot reproduce

While the properties of natural materials are determined by their chemistry, the properties of metamaterials depend instead on their physical structure. In the case of the new cloak, that structure consists of copper rings and wires patterned onto sheets of fibreglass composite that are traditionally used in computer circuit boards.