The magnetic field and induced current arising from a cylindrical shell loop with an unbalanced current

This paper addresses the magnetic field and induced current associated with a cylindrical shell loop under the excitation of an unbalance current source. An equivalent circuit theory is introduced to describe the coupling effect when the cylindrical shell loop is formed. Close-form expressions of the circuit component parameters are derived, as well as the induced current and magnetic field. An experimental validation of the theory is presented. It is demonstrated that an electrically "isolated" cylindrical shell has no shielding effect, and effective shielding results if an opposite electric current flows along the cylindrical shell. Any additional resistance introduced in the loop will degrade the shielding performance.