Electromagnetic wave absorbing performances with Fe₂O₃ nanotubes/reduced graphene oxide composite sponge

Electromagnetic wave absorbing materials which are low in cost and light weight are highly desirable, especially if they can be easily manufactured. A special Fe₂O₃ nanotubes /reduced graphene oxide (RGO) composite sponge with a 3D (three dimensional) plus 2D (two dimensional) structure was produced. The Fe₂O₃ nanotubes /RGO composite sponge exhibits excellent microwave absorption capacity. Different amounts of Fe₂O₃ nanotubes in the RGO sponge work well in improving absorption effectiveness. Specifically, by using a small amount of Fe₂O₃ nanotubes, the desired absorption bandwidth gets to 8.7 GHz and obtains the best attenuation property among other samples tested, and with a moderate number of Fe₂O₃ nanotubes added which exhibits an outstanding degree of impedance matching performance. A large amount of Fe₂O₃ nanotubes will narrow down the desired absorption bandwidth, but it will enhance the minimum reflection loss. These excellent performances of the composites originate from the altered dielectric constants, scattering parameters and the unique multi-dimensional structure. A good microwave absorber should have a good impedance matching performance with an effective attenuation property at the same time. It can be concluded that having low S11 value is expected to have a good matching performance while S21 value can be a sign of microwave dissipation ability.