Centimeter- and Millimeter-Wave Attenuation Properties of Carbonyl Iron Fiber-Filled Foam Composites

We have formulated carbonyl iron fiber-filled foam composites and measured their complex permittivity and permeability at x-band (8.2-12.4 GHz) by the transmission and reflection waveguide method. The results show that carbonyl iron fiber with smaller diameter and higher aspect ratio exhibits higher complex permittivity and permeability. The reflection loss measurement shows that lightweight carbonyl iron fiber-filled foam composites possess good absorbing properties in both centimeter- and millimeter-wave bands.