Electromagnetic wave absorption properties of carbonyl iron-ferrite/PMMA composites fabricated by hybridization method

The surface of carbonyl iron powder or a mixture of carbonyl iron and ferrite was coated with polymethylmethacrylate (PMMA) microspheres by a hybridization method to make hybrid powders, and then electromagnetic wave absorption properties of the hybrid composites prepared with these hybrid powders have been investigated. As for the carbonyl iron/PMMA hybrid composite, the reflection loss less than −20 dB could be achieved in a frequency range of 1.7–5.0 GHz when the composite thickness was below 5.00 mm. In the case of the carbonyl iron-ferrite/PMMA hybrid composite, a similar reflection loss was observed in a frequency range of 4.3–13.0 GHz. Thus, the addition of ferrite was found to be useful for achieving a large absorption in a wide frequency range, especially for higher frequency values. Simulated values for the minimum reflection loss are well agreed with actually measured ones, because of homogeneous distribution of carbonyl iron and/or ferrite in these hybrid composites.