Relationship Between Shielding Characteristics and Winding Pitch of the Magnetic Ribbon in the Cylindrical Shielding Case

In fabricating a cylindrical case from magnetic ribbon for shielding, the ribbon has to be wound helically on the outer surface of a cylinder. In this paper, we studied the relationship between the shielding characteristics for transverse and axial disturbing fields and the winding pitch of the magnetic ribbon. The shielding factor is high when the angle between the direction of the disturbing field and the longitudinal direction of the magnetic ribbon is small. For example, the shielding factor S¿ for a transverse field was 220 at a winding angle of ¿=10°, while S¿=200 at ¿=30° and S¿=160 at ¿=45°. Leakage of the shaking field into the shielded space was reduced by decreasing the winding pitch.