The preparation and high-frequency electromagnetic properties of Co80Ni20 alloy particles for potential antenna applications

Abstract A magneto-dielectric substrate material with high permeability and low loss at high frequency is necessary for a miniaturized antenna. Keeping the loss low is essential, in order to restrain the eddy current effect and to possess a high magnetic resonance frequency. In this work, the effects of the NaOH concentration and soaking time on crystal structures and morphologies of Co80Ni20 alloy particles are studied based on a polyol process. The results reveal that the size of particles increase with the promotion of the concentration of NaOH and soaking time. The electromagnetic (EM) properties of Co80Ni20 alloy particles/ polyurethane composites with various soaking times are studied at the NaOH concentration of 1.5 mol/L. The results reveal that the real part of permeability ( μ ' ), the real part of permittivity ( e ' ), the magnetic loss tangent (tan δ μ ), the dielectric loss tangent (tan δ e ) of the composite with the soaking time of 3 h are 2.0, 11.0, 0.09, and 0.057 at 1 GHz, respectively, and the eddy current effect is suppressed effectively. The calculation of the permeability shows that the composite possesses a high domain wall resonance frequency. This work is significant for developing a magneto-dielectric substrate material using at 1 GHz.