Abstract: Carbon nanotubes (CNTs), with well defined one-dimension nanoscale tubular structure, have potential applications for elctromagnetic wave absorption. The complex permittivity and permeability spectra of different kinds of CNTs were measured in the range from 2 GHz to 18 GHz. The coefficient of attenuation, impedance and loss tangents of different kinds of carbon nanotube composites were compared. The order of loss tangents is as follows: aligned multi-walled CNTs > raw tangled multi-walled CNTs > purified tangled multi-walled CNTs > raw tangled single-walled CNTs > purified tangled single-walled CNTs. The reflectivities of different kinds of carbon nanotube composites were calculated. Compared with multi-walled CNTs, single-walled CNTs have wider absorption capability. Both experimental and calculated results indicated that CNTs as filler in nano-composite materials have excellent elctromagenetic wave absorption properties.

Key words: Single-walled carbon nanotubes, Multi-walled carbon nanotubes, Electromagnetic wave absorption