Control of magnetic loss profile for RF noise suppression sheets

The ideal frequency profile of magnetic loss /spl mu/" for the magnetic composite sheets to be used as high performance RF noise suppressors is a steep rise of at the critical frequency followed by gradual decay of 1/f. We testify that the /spl mu/" profile can be improved by combining the multiple elemental dispersion of /spl mu/" and applying magnetic field. Furthermore, patterning of the sheets into a stripe array works effectively to reduce the strength of the external field because of enhancement of the shape anisotropy. Consequently /spl mu/" profile closer to that of the ideal RF noise suppressor is obtained.