Survey of the passive protection on board of the ship against low and high frequency electromagnetic fields

The study of the shielding materials used in shipbuilding is an important element both for the protection of electronic systems onboard ships and of the crew against electromagnetic disturbances. By its approach, this paper has as a starting point, a brief presentation of the calculation method for determining the attenuation expression, by reflection and absorption, known as the impedance method, for a common frequency range between 50 Hz and 20 GHz. for both civilian and military vessels. Also, some aspects of the shielding of the near fields (at low frequencies) and of the far-field (at high frequencies) are analyzed. Based on the theoretical study and some of the magnetic and non-magnetic materials properties, several solutions have been proposed in order to reduce the effects of these types of electromagnetic fields.