Low-Loss Composite Material Containing Fine Zn–Ni–Fe Flakes for High-Frequency Applications

A low-loss magnetic composite material consisting of Zn₅Ni₇₅Fe₂₀ fine flakes dispersed in a polymer has been developed for miniaturization and performance improvement of high-frequency devices. Fine flakes are produced by a new mixing procedure that prevents cohesion of particles, thereby enhancing the dispersibility of the particles. The complex relative permeabilities of the developed material are mu\´ = 2.4, mu" = 0.09, and tan deltamu( = mu"/ mu\´) = 0.04 at 1 GHz. The low-loss properties of the developed magnetic composite material are confirmed by measured and simulated results of the basic characteristics of a small helical antenna loaded with the developed material.