The present disclosure relates to a slotted waveguide antenna system. The slotted waveguide antenna system includes a waveguide that includes a first surface and a plurality of slots defined in the first surface and a metamaterial structure positioned external to the waveguide. The metamaterial structure is configured to exhibit a negative effective permittivity and a negative effective permeability for an operating frequency range. The metamaterial structure includes a split ring resonator, a substrate and a wire structure. The wire structure includes a first portion, a second portion and a third portion, the second portion coupled between the first portion and the second portion, the first portion oriented parallel to the third portion, the second portion oriented perpendicular to the first portion and the third portion. A dimension of at least one of the first portion and the third portion is related to the operating frequency range.