Study of electromagnetic shielding effectiveness of metal oxide polymer composite in their bulk and layered forms

In this paper, we present the studies on electromagnetic interference (EMI) shielding effectiveness (SE) of K₂CrO₄-PMMA composites developed by two different methods: one in bulk form of thickness 1.2 mm and another by stacking twelve layers of thin films each of thickness 100 μm. The EMI SE of stacked twelve layers of 1.2-mm-thick composite films has been achieved until 23.2 dB in the frequency range 8.0-12.0 GHz. This is remarkably higher than the 17 dB achieved for the bulk composites of 1.2 mm thickness. The characteristic EMI SE graphs obtained using Agilent E82B Vector Network Analyzer in the X band frequency range have been depicted, and the shielding mechanism in these composites has been analyzed. It is found that the SE in this frequency range is dominated by absorption. The study suggests these composites to be a potentially promising material for EMI shielding purpose.