L’impiego di metamateriali per aumentare considerevolmente la trasmissione attraverso un piccolo foro in uno schermo opaco

In this work, we theoretically and numerically show the role of properly selected pairs of metamaterial layers, one located in the front and the other in the back surface of a small sub-wavelength hole in a conducting opaque screen. In recent years, there have been experiments in the optical regime conducted by several groups of physicists all over the world showing how an appropriately designed periodic corrugation on a metallic opaque screen leads to significant increase of the power transmission through a subwavelength hole. Oliner, Jackson and their co-workers explained and justified this power enhancement as the result of the excitation of the leaky waves supported by the corrugated screen. In the present work, we suggest a different configuration using metamaterial bilayers covering the entrance and the exit face of the hole in a flat PEC screen. In this setup, one pair of metamaterial layers effectively “collects” the power of the incident wave and concentrates it at the entrance of the hole, the other pair of layers at the exit face further increases the anomalous tunneling and re-shapes the radiation patterns at the receiver side. Conditions for the optimal transmission and certain physical insights will be presented, together with numerical results confirming our theory.