Abstract
The absorption characteristics of ferrite composites using SiO2 (70mol%) with the average grain size of approximately 30nm, 12nm and 7nm became larger than that of ferrite composites using SiO2with the average grain size of approximately 29μm in the low frequency region. For the ferrite composite using fine grain Ni-Zn ferrite and Si02 with the average grain size of approximately 29μm, simulated values of the frequency dependence of the average complex permeability μ_r* was similar to that of Ni-Zn ferrite in the low frequency region, though it is smaller than that of Ni-Zn ferrite. The average complex permeability μ_r* of the ferrite composite was larger than that of Ni-Zn ferrite in the high frequency region. For the ferrite composite made of fine grain Ni-Zn ferrite(20mol%) and SiO2 (80mol%) with the average grain size of approximately 29μm, it could absorb electromagnetic waves above 90% in the wide frequency region like Ni-Zn ferrita in the low frequency, at the same time it could absorb electromagnetic waves above 90% in the high frequency region by simply changing the thickness.
