M. Selvanayagam, G. Eleftheriades

Published nearly the same time as the Chen paper, a second paper by Selvanayagam and Eleftheriades actually provided an experimental demonstration of an active cloak. The Selvanayagam cloak involved a 12-element, active magnetic-dipole array encircling an aluminum cylinder. Sensing the incoming wave, the active circuits then create counter-currents that cancel the scattering of the cylinder—in some sense, like noise cancellation headphones! These fascinating papers are hopefully just the beginning of the era of active cloaking.