Transmission enhancement from a sub-wavelength hole in a perfect electric screen through the employment of new setups based on SNG metamaterials

New setups employing SNG metamaterials: physical explanation of their operation and full-wave numerical results is discussed. A perfect electric screen with a sub-wave length circular hole is sandwiched between two different SNG metamaterial slabs. The thickness of the metallic screen is assumed to be extremely small, so that the retardation effects due to the propagation of the field through the hole can be neglected. We propose at first to place the MNG slab at the entrance face and the ENG slab at the exit