Isotropic three-dimensional left-handed metamaterials

We investigate three-dimensional left-handed and related metamaterials based on a fully symmetric multigap,single-ring split-ring resonator (SRR) design and crossing continuous wires. We demonstrate isotropic transmission properties of a SRR-only metamaterial and the corresponding left-handed material that possesses a negative effective index of refraction due to simultaneously negative effective permeability and permittivity. Minor deviations from complete isotropy are due to the finite thickness of the metamaterial.