Magnetic Shield Effectiveness in Low Frequency

Abstract

Since the early days of radio and telegraph communications, it has been known that a spark gap generates electromagnetic waves rich in spectral content (frequency components) and that these waves can cause interference or noise in various electronic and electrical devices such as radio receivers and telephone communications. Electromagnetic pulses are fields of energy that they can damage electrical and electronic circuits at once. New technology of microelectronic circuits is sensitive to interference power. An intentional or inadvertent risk and unforeseen create irreparable damages, so that it is important to investigate electromagnetic interference from viewpoint: generation source, the effectiveness on electronic components and safekeeping methods. One of the prevalent methods for safekeeping against these pulses is shielding. In this paper, at first, the effect of magnetic field intensity is investigated in frequency selected (0-545Hz) for various shields such as: paramagnetic materials, diamagnetic materials and ferromagnetic materials and shielding effectiveness is calculated for various low frequencies in one point in shield and shielding effectiveness variation with increase in frequency for any material is obtained. In The following of paper, the effect of magnetic field intensity is investigated on shield's two apertures and six apertures. Then, the apertures are displaced on shield surface and shielding effectiveness variation is obtained. This apertures displacement has done for various shield materials. Finally, the effects of composite shields are studied to shielding effectiveness. These shields have combined to two materials. We obtained interesting results from composite shields. In this paper, solution method has chosen 2DFEM and the whole of simulations have done Cosmos/M.