Using unconventional materials for electromagnetic shielding

An exploratory frequency domain shielding performance analysis was performed from 1 kHz to 20 GHz to determine what kind of electromagnetic enclosure shielding performance would be expected if non-conventional materials or techniques were used rather than conventional metal construction. In order to cover the wide frequency range, three coupling mechanisms were used (wall transfer impedance, aperture polarizability and aperture excitation of an electrically large cavity). Four enclosures (two sizes, two materials-one aluminum, one plastic with nickel on copper plating) were used to represent typical equipment enclosures. Below 100 MHz, shielding performance was determined by the wall material. Above about 100 MHz, the kind of apertures found in practical enclosures were more important than the wall material.