Simulation Research Of Magnetic Shielding Technology

Base on the electromagnetic radiation having negative effects upon human health,economic construction and national defense construction，it is the urgent internationalissues to be addressed that develop more and more efficient magnetic shieldingsolutions preventing environmental pollution of the electromagnetic radiation toprotect environment and human health, avoiding the leakage of electromagnetic wavesto ensure the information security. The shielding prop erties of electromagneticshielding materials are analyzed in the paper, a three-dimensional finite elementmethod (FEM) analysis is performed to evaluate the magnetic characteristics of thecylindrical shell immersed in a steady uniform magnetic field gen erating by thecopper coil on the iron core. The shielding properties of the high permeabilitymaterial, the high electrical conductivity material and the superconducting materialare studied．First, the analysis was performed to investigate the potential of magneticshielding of systems with the thickness aspect ratio exploiting the opposite magneticproperties of ferromagnetic materials such as iron. The results of simulationdemonstrate the higher values of the shielding factor(SF) at thicker shielding material.Second, the cylinder of good electric conductors such as aluminium is effective inshielding alternating magnetic field, the results of simulation show the higher SFvalues at thicker shielding material, and the higher SF values at higher frequency,though they have low performance in the case of a low-frequency magnetic fieldwhere there is no skin effect. In this paper we focus on the shielding properties of ahybrid Al/Fe structure consisting of two coaxial cylinders subjected to an internalmagnetic field parallel to their axis, the height of each cylinder are chosen of similarvalues in order to analyze the shielding potential of the materials in alternatingmagnetic field, the hybrid solution gives higher shielding factors than those of thealuminium cylinder alone. The hybrid solution demonstrate the feasibilities andadvantages, but also make fundamental effort for following exploration of theproducts based on the shielding material. Finally, when a cylinder of superconductingmaterial is immersed in a magnetic field such as the static magnetic, low-frequencyalternative magnetic field and high-frequency alternative magnetic field, currents arecaused to circulate in the superconductor in such a manner as to tend to cancel the magnetic field in the interior of the body, this effect is known as the Meissner effectand results in the reduction of the magnetic field strength in the interior of thesuperconductor. The results of simulation indicate superconducting material is themost efficient magnetic shielding solution.The problem of optimal magnetic shielding method for different magneticshielding materials is to be solved. The new technologies are explored for improvingthe efficiency of the magnetic shielding, services to the social life, national economyand defense industries, which has important theoretical and applied significance forthe electromagnetic compatibility problem to be solved.