| The dissertation of this paper is to find the basic theory and experimental data for the material which is utilized as a electromagnetic interference suppression in the high frequency broad band. According to magnetic dissipation and interference suppression theory of Sendust alloy, this paper chiefly discussed five opinions to overcome the defects of EMI suppression material at present such as low properties in high frequency and narrow suppression band and so on.Firstly, the theory of electromagnetic field and theory of ferriomagnetism were combined to analyze the energy dissipation mechanism of Sendust alloy in low and high frequency. It is the point that eddy dissipation of magnetic dissipation mainly gives the cause for material energy dissipation in low frequency and in high frequency the natural resonance and ferromagnetic resonance take over from it. Then variation characteristic of material magnetic spectrum as a function of magnetic properties and powder micro-configuration has been found for the selection and manufacture of materials.Secondly, based on the mechanism of material energy dissipation and magnetic spectrum characteristics, the factors that application of soft magnetic alloy in high frequency is limited are analyzed. Then the selected manufacture technology of soft magnetic alloy complex material was generated,EMI suppression material had been manufactured step by step according to the technology. The material size and its properties were measured.Last, it was investigated in theory how to select and manufacture the suppression material depending on the given conditions of electromagnetic interference.
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