Metamaterial bilayers for enhancement of wave transmission through a small hole in a flat perfectly conducting screen

In this talk, we theoretically demonstrate the role of two 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 flat perfectly electric conducting (PEC) screen. In recent years, there have been experiments in the optical regime conducted by others 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 et al. (2003) 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 re-shapes the radiation patterns in the receiver side. Conditions for the optimal transmission and certain physical insights are presented, and some numerical results confirming the theory are also shown.