Microwave Permeability of Ferromagnetic Microwires Composites/Metamaterials and Potential Applications

Composites with regularly or randomly distributed CoFeNiSiB ferromagnetic microwires were fabricated and characterized. Permeability of such composites were investigated with impedance and coaxial line methods from 1 MHz to 10 GHz. High magnetic permeability and loss were obtained from composites with low volume fraction of microwires, which can be explained by materials and shape anisotropy. The reflectivity of microwire composite to incident wave calculated from measured permeability and permittivity shows potential for high attenuation applications. Negative magnetic permeability found between 0.5 to 5 GHz may also be employed to fabricate metamaterials with negative refraction index.