Carbon nanotube composites for broadband microwave absorbing materials

In this paper, we present a shielding and absorbing composite based on carbon nanotubes (CNT) dispersed inside a polymer dielectric material. The extremely high aspect ratio of CNTs and their remarkable conductive properties lead to good absorbing properties with very low concentrations. A broadband characterization technique is used to measure the microwave electrical properties of CNT composites. It is shown that a conduction level of 1 S/m is reached for only 0.35 % weight percent of CNT, while for a classical absorbing composite based on carbon black 20 % concentration is mandatory.