Optimization of electromagnetic matching of Fe-filled carbon nanotubes/ferrite composites for microwave absorption

Abstract

Composite microwave absorbers have been fabricated by Fe-filled carbon nanotubes (CNTs) and a W-type hexagonal ferrite. The microwave absorption of the absorbers can be tuned by matching the dielectric loss and the magnetic loss by changing the ratio of ferrite in the composites. The microwave absorbing properties of the absorber are evidently improved as compared with the absorber containing only CNTs or ferrite. The reflection loss of the composites with 40 wt% ferrite and 6.2 vol% CNTs at 2.0 mm thickness reached 21.9 dB at 8.5 GHz. The maximum absorption capability of 50.5 dB GHz was obtained at a ferrite concentration of 60 wt%. With the increase in the weight percentage of ferrite in the composites the resonance absorption peak shifted towards the lower frequency region.

A new microwave absorber based on antimony-doped tin oxide and ferrite composite with excellent electromagnetic match

“…The real (ε ) and imaginary (ε ) parts of the complex permittivity spectra of microwave absorbers (sam- polarization and intrinsic electric dipole polarization. The interfacial polarization absorption comes from the interaction of the electromagnetic wave with multipoles at the interfaces between different absorbents [12]. In the present composite absorbers, interfaces between ATO and ferrite are beneficial to the interfacial polarization absorption.…”

“…In recent years, a number of investigations have been well documented on the composite microwave absorbing materials based on ferrite [8][9][10][11]. For examples, carbon nanotube is compounded with ferrite due to its high complex permittivity [12], and polyaniline is compounded with ferrite because of its controllable resistivity [13]. It is well known that antimony-doped tin oxide (ATO) has low resistivity which may be useful to adjust the resistivity of ATO-based composites [14].…”

Microwave absorption properties of multi-walled carbon nanotube (outer diameter 20–30nm)–epoxy composites from 1 to 26.5GHz

“…We note here that different types of CNTs have been studied for their use in MA [22]. Compared with single-walled CNTs (SWCNTs), multiwalled CNTs (MWCNTs) have more defects due to their complicated structure and higher permittivity.…”

Design of mesostructured γ-Fe2O3/carbon nanocomposites for electromagnetic wave absorption applications

“…Recently, the development of carbon-based materials with designed pore architecture may provide the possibility of a promising candidate for microwave absorbers, especially in the cases of light weight and harsh environment [3][4][5][6][7]. Their unique structure and properties can be utilized to overcome the shortcomings of conventional microwave absorbing materials [8][9][10][11][12][13].…”