Absorption of electromagnetic waves by Fe₃O₄/paraffin composite materials

Electromagnetic pollution in general and the harmful effects of microwave radiation in particular on environment is currently in the urgent stage. To eliminate the effect of electro-magnetic energy the most common methods relies on the use of absorbing materials with large absorption capacities in wide frequency band. In this paper, we investigate the capability of ab-sorption of electromagnetic waves of Fe₃O₄nanoparticles in paraffin basis. The Fe₃O₄/paraffin composite materials were prepared with a weight ratio of 35%/65%. The dielectric constant (εr) and the magnetic permeability(μr)in the frequency (f)range from 8 to 18 GHz were measured for various sample thicknesses. The results indicated a large dielectric loss and strong thickness dependence of absorption capacity. The maximum absorption coefficient (RL) is of order -13.6dB, corresponding to the achieved absorbance of 96.9% for the 2.6 mm of sample thickness. The experimental results are consisted with our simulation calculation. (author)