Negative index material composed of electric and magnetic resonators

Negative index-of-refraction materials (NIMs) require both the electric permittivity and the magnetic permeability of the material to be negative. Most reported NIMs have combined conducting split ring resonators (SRRs) to realize the magnetic response and nonresonant wires to realize the electric response. Here, however, the authors demonstrate an impedance-matched, relatively broadband NIM which makes use of SRRs and electric resonators, tuned such that they resonate at the same frequency and with nearly the same frequency dispersion. The NIM properties are confirmed by direct measurements of the phase variation and field distributions, obtained by field mapping.