Theoretical analysis and numerical simulation of electromagnetic parameters of Fe-C coaxial single fiber

Based on the Maxwell equation, the electromagnetic model in the coaxial fiber was described. The interaction with electromagnetic wave was analysed and the theoretical formula of axial permeability (mu(parallel to)), axial permittivity (epsilon(parallel to)), radial permeability (mu(perpendicular to)) and radial permittivity (epsilon(perpendicular to)) of Fe-C coaxial fiber were derived, and the demagnetization factor (N) of fibrous material was revised. Calculation results indicate that the composite fiber has stronger anisotropy and better EM dissipation performance than the hollow carbon fiber and solid iron fiber with the same volume content. These properties can be enhanced through increasing aspect ratio and carbon content. The mu(parallel to) is 5.18-4.46i, mu(perpendicular to) is 2.58-0.50i, epsilon(parallel to) is 7.63-6.97i, and epsilon(perpendicular to) is 1.98-0.15i when the electromagnetic wave frequency is 5 GHz with the outer diameter of 0.866 lm, inner diameter of 0.500 mu m, and length of 20 mu m. The maximum of the imaginary part of mu(parallel to) and epsilon(parallel to) are much larger than that of mu(perpendicular to) and epsilon(perpendicular to) when the structural parameters change, and the maximum of mu(parallel to) and epsilon(parallel to) can reach 6.429 and 23.59. Simulation results show that greater conductivity, larger aspect ratio, thin iron shell play important roles to improve the electromagnetic matching ability and microwave attenuation for the Fe-C coaxial fibers. (C) 2017 Elsevier B.V. All rights reserved.