Temperature dependence of electrical parameters of SMD ferrite components for EMI suppression

This paper presents how electrical characteristics of ferrite EMI suppressors depend on the operating frequency and temperature. These multi-layer surface-mounted components consist of conductive platinum layer embedded in the middle of nickel-zinc ferrite monolithic structure. In order to analyze variation of performances with temperature changes, a simulation tool has been developed to predict behavior of the SMD ferrite components for EMI suppression. Results for the impedance and inductance as a function of frequency in the temperature range from +25 °C to +120 °C are presented. Proposed EMI suppressors were experimentally tested in the frequency range 1 MHz-1 GHz using an Agilent 4191A RF Impedance analyzer. The calculated results were in very good agreement with the measured ones.