Analysis on noise suppression effect of the composite magnetic sheet for the use in near field

The noise suppression sheet made of composite magnetic material, is now widely used in so many electronic components, for countermeasuring an electromagnetic noise in quasi-microwave band. Calculation analysis has been made to evaluate the suppression effect of the sheet due to its magnetic loss in high frequency. Authors have calculated transmission and radiation characteristics of the microstrip line attached with the noise suppression sheet using FDTD method, and confirmed that the magnetic loss of the material is the dominant factor of the absorption, and also there was seldom radiation.