New carbon nanotube-epoxy composite for dampening microwave cavity resonance

We studied the dampening effect of multiwalled carbon nanotubes (MWNTs)-epoxy composite to microwave cavity resonance. Six groups of MWNT-epoxy composite samples with different MWNT outside-diameters (OD) were fabricated and tested. The weight percentages of MWNTs in each sample group were in the range of 1-10%. In general, the MWNTs with smaller outside-diameters had higher microwave dampening efficiency at 9.968 GHz than the larger ones. The SEM analysis and microwave measurements showed that the microwave dampening efficiency of the CNTs was also affected by the morphologies of MWNTs in individual bundles. A higher density of MWNTs in CNT bundles results in relatively lower efficiency in dampening the microwave fields at the central frequency of 9.968GHz.