Resonance transformation of the field of a linear source into multipole radiation with the help of a cylindrical metamaterial layer

A hollow circular metamaterial cylinder with a negative permittivity and a negative permeability is considered. The 2D problem of excitation of the cylinder by a filament source is numerically investigated. It is found that, when the relative permittivity and permeability are close to minus unity, high-Q resonances exist in hollow cylinders of an electrically small diameter. It is shown that, when the cylindrical wave source is situated inside the cavity, omnidirectional radiation is transformed at the resonance frequency into multipole radiation with a large number of identical lobes in the pattern. Near- and far-field patterns are calculated. The influence of loss on the resonance characteristics is investigated.