Shielding improvement of multilayer enclosure at low frequency

To shield low-frequency magnetic field is necessary to surrounding the entire volume of interest with ferromagnetic metal barriers. However it is as much known that a good ferromagnetic material is more expensive especially with high permeability ferromagnetic material and also is very heavy. An adequate and cheaper possibility is the use of a multilayer screens. In this paper, we have investigated a simple way to design a multilayer shield obtained as inclusion of conducting shield enclosure and magnetic shield enclosure, in order to valuate the attenuation of the magnetic field generated by a loop antenna transmission at industrial frequency. We have simulated our multilayer shield model with Opera Vector Field® simulator, and compared the results with experimental shielding effectiveness measurements made on a prototype of the multilayer screens enclosure. Experimental data shown a quite agreement with the theoretical model, highlighting as useful is this light weight multilayer screen, in the magnetic field shielding for industrial frequency rate.