Analysis, design, and characterization of ferrite EMI suppressors

In this paper design, modeling and characterization of single and double coils, which consist of conductive layer embedded in the soft ferrite material, are described. These surface-mount components, comprising of a cofired multilayered ferrite and coil, have been developed in the ceramic coprocessing technology. A simple analytical model of proposed structures is presented. This model is very suitable for circuit simulations and for prediction of frequency characteristics of considered inductors. The inductance and impedance of coils embedded in low permeability or high permeability ferrite material are calculated and compared. Also, these suppressors were experimentally tested in the frequency range 1 MHz–3 GHz using an Agilent 4287 A RF LCR meter. The calculated results were in good agreement with the measured ones. Index Terms—EMI suppressor, high-frequency characteristics, impedance and inductance calculation, single and double coils