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.
M. Selvanayagam, G. Eleftheriades
Physical Review X
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