EFFECTIVE SHIELDING OF UNIDIRECTIONAL CURRENT GENERATED MAGNETIC FIELDS

This paper presented an effective shielding design of magnetic fields generated by unidirectional current. Theoretical formulas and numerical computation software based on boundary element method (BEM) are employed to evaluate the shielding effectiveness (SE) of cylindrical shell. It is shown that ungrounded or one end grounded metal shell is ineffective for such magnetic fields. SE can be obtained by connecting the two ends of the conducting shell with low impedance connector, or alternatively, grounding the two ends. The experimental results also support these conclusions.