Simple Formula for the Calculation of Shielding Effectiveness of Finite Width Conductive Shields

In this paper, a fast and simple analytical formulation for the calculation of the shielding effectiveness of finite width conductive shields at extremely low frequency is proposed. The magnetic field generated by a current loop is analysed considering a conductive shield of various widths and for different distances of the source from the shield and from the field point. The effect of the system parameters on the shielding effectiveness is investigated. A formula for the shielding effectiveness of finite width conductive shields at extremely low frequency is derived from the values of the magnetic field in absence of the shield and in presence of a shield of infinite extension.