S-SHAPED RING RESONATOR AS ANISOTROPIC UNIAXIAL METAMATERIAL USED IN WAVEGUIDE TUNNELING

In a novel application a slab of S-shaped ring resonators is used in the form of an anisotropic uniaxial metamaterial with transversal negative effective permeability to fill a rectangular waveguide. Theory and experimental results show that the operational bandwidth of the dominant mode can be extended below the cutoff frequency with low insertion loss. On the other hand, this structure can be used as a band-rejection filter with adjustable bandwidth. The stopband bandwidth can be varied from few MHz to GHz. The width of the stopband can be decreased by increasing the distance of the slab from the central plane of waveguide.