Abstract
A new structure of negative-refractive-index material is proposed, which is composed of ferromagnetic wires setting in two-dimensional Bravais lattice (FWL) with the application of external magnetic field. The refractive index of the FWL consisting of ferrum wires arranged in square lattice is calculated. The refractive index exhibits negative value in the GHz region. A notable characteristic of the FWL is that the negative refractive index is tunable by the applied external field.