Enhanced electromagnetic absorption properties of carbon nanotubes and zinc oxide whisker microwave absorber

CNTs/ZnOw composites were fabricated by a simple mechanical mixing method. The effects of the different CNTs and ZnOw mass fractions on the electromagnetic parameters and wave absorbing properties of the composites were studied. The complex permittivity and attenuation constant increase with increasing mass fractions of CNTs and ZnOw. However, the microwave impedance decreases with the increasing concentrations of CNTs and ZnOw. The experimental results show that 4 wt% CNTs mixed with 10 wt% ZnOw has the optimum microwave absorption ability with a thickness of 2.0 mm. The minimum reflection loss is -37.03 dB at 12.24 GHz and the bandwidth corresponding to the reflection loss below -10 dB is more than 4.04 GHz. Compared with pure CNTs or ZnOw, it cannot only greatly reduce the mass fractions of microwave absorbing materials, but also enhance the microwave absorption properties. The results indicate that the prepared CNTs/ZnOw composites have excellent absorbing properties with thin thickness and lightweight. (C) 2011 Elsevier B.V. All rights reserved.