P-Y. Chen, C. Argyropoulos, A. Alu

Adding energy to a passive material can increase the bandwidth of invisibility cloaks. Chen and colleagues propose a thin metasurface that can reduce the scattering from a cylindrical object over a fairly large band of frequencies. Unlike most cloaks demonstrated to date, which are made using only passive metamaterials, the “non-Foster” cloak would be wired up with tiny electronic circuits that actively cancel the scattering that would otherwise be present from the cylinder.