Broadband microwave absorbing materials based on MWCNTs' electromagnetic wave filtering effect

Broadband microwave absorbing materials with a multilayer structure based on multi-walled carbon nanotubes (MWCNTs) as a filtering layer has been designed. The absorption curves of the multilayer structure change from a single peak to double peaks after the addition of the filtering layer. As a result, the effective microwave absorption bandwidth is broadened to 12.6 GHz with a total thickness of 2.3 mm. Normalized power flow and power loss distribution maps at fixed frequencies were analyzed by CST simulator. The broadening of the microwave absorption bandwidth is attributed to the electromagnetic wave selective filtering effect of the MWCNTs which contribute to impedance matching and microwave absorption at different frequencies.