The effects of shape anisotropy of the magnetic particles in a composite on RF power absorption

The shape anisotropy of the magnetic particles in a composite film for EMI applications plays a key role in their performance. For a few types of the particles such as wires and hollow fibers, permeabilities of the particles and in-line attenuation of the composite were evaluated by simulations. With the change of the shape anisotropy by aspect ratio or hollow ratio, power absorption could be controlled in frequency. In experiments, Ni/FeCo magnetic hollow fibbers were fabricated by electroless plating and power loss of the composite filled with the fibbers was evaluated.