Composite medium with simultaneously negative permeability and permittivity

We demonstrate a composite medium, based on a periodic array of interspared conducting nonmagnetic split ring resonators and continuous wires, that ex hibits a frequency region in the microwave regime with simultaneously negat ive values of effective permeability mu(eff) (omega) and permittivity epsil on(eff)(omega) This structure forms a "left-handed" medium, for which it ha s been predicted that such phenomena as the Doppler effect, Cherenkov radia tion, and even Snell's law art inverted. It is now possible through microwa ve experiments to test for these effects using this new metamaterial.