No abstract

This paper presents conditions of a laminated sheet composed of copper and magnetic sheets for obtaining wideband shielding effectiveness below 10 MHz. The following two conditions are clarified: (1) the optimum thickness ratio of the copper sheet to the laminated sheet is 0.5-0.7, (2) the loss factor (tanδ) of the relative permeability of the magnetic sheet is above 1 for increasing reflection losses of the laminated sheet. These conditions are validated by measuring the shielding effectiveness of the laminated sheet. The shielding effectiveness of the laminated sheet is higher than that of the copper sheet in the frequency from 0.1 MHz to 10 MHz.