Design and demonstration of a metamaterial with electronically tunable negative refraction across the C microwave band

The design, numerical simulation and experimental measurement of a novel metamaterial with an electronically tunable negative refractive index region are presented. The proposed unit cell is loaded with commercial varactors operating over the C microwave band. Tunability is achieved by applying a static electric field across the series-connected split-ring resonators. A theoretical description of the unit cell is correlated with microscopic and macroscopic simulations of the proposed metamaterial. Two samples of the proposed metamaterial are evaluated in a waveguide measurement. The wideband tunability of the proposed metamaterial is well suited to a variety of microwave applications.