Electromagnetic anisotropy of magnetic iron fibres at microwave frequencies

The theoretical formulae of electromagnetic parameters of magnetic metal fi bres were derived. Based on these formulae, the microwave electromagnetic p arameters of magnetic iron fibres were calculated. The calculated results s how that the magnetic iron fibres exhibit strong electromagnetic anisotropy at microwave frequencies; the permeability mu (parallel to) parallel to th e fibre is higher than the permeability mu (perpendicular to) perpendicular to the fibre; the permittivity epsilon (parallel to) parallel to the fibre is significantly higher than the permittivity epsilon (perpendicular to) p erpendicular to the fibre. Magnetic iron fibres of diameter about 2-5 mum w ere fabricated by the bundle-drawing method and anisotropic samples were pr epared by dispersing iron fibres randomly in paraffin. During the preparati on of the samples, a magnetic field was applied to orient the iron fibres. A method for determining the microwave electromagnetic parameters of anisot ropic samples was described in great detail. Using this method, the electro magnetic parameters of the anisotropic samples containing oriented iron fib res were measured in the S band. The measurement results validated the elec tromagnetic anisotropy of the magnetic iron fibres.