Application of epoxy/carbon nanotube composites as microwave absorber at frequencies up to 25 GHz

A new type of Epoxy/CNT composite has been fabricated based on bisphenol A-epoxy resin, loaded with 0.5wt% of commercial multiwall carbon nanotubes. Exploiting the resulting high conductivity of this composite material, we tested the possibility to use it as absorber of electromagnetic waves at microwave frequencies up to 25 GHz. For this purpose the sample, to be tested, was placed as substrate of a microstrip transmission line. Measurements of the scattering parameters, done with a vectorial network analyzer, have been used in order to obtain the power absorption (PA) spectra. Special attention was paid to the optimization of the microstrip geometry. A comparison of the PA spectrum with the absorption spectra of commercial cavity absorbers showed encouraging results, regarding the microwave absorption capability of the new nanocomposite material.