Electromagnetic Properties and Absorption Evaluation of Processed Carbonyl Iron and MWCNT at PANI Nanocomposites in the <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math> </inline-formula>-Band

Abstract

Composites loaded with various carbonyl iron-based (CI) materials are fabricated and characterized with regards to their electromagnetic properties and absorption in the X-band (8–12 GHz). The combination of inclusion CI particles and multiwalled carbon nanotubes (MWCNT) is also explored. To this effect, CI micropowder has been successively processed to get the form of flaked, porous, and nanosized TiO2-coated particles, whereas MWCNT has been coated with polyaniline (PANI). The processed fillers were primarily characterized to verify their structural consistency and large variations in the microstructure. The static magnetic properties of the CI-based powders have been analyzed via the vibrating sample magnetometry. Finally, complex dielectric permittivity and magnetic permeability spectra along with the return loss (RL) maps of composites loaded with the powders under study have been extensively investigated. Among the studied samples, the multicomponent composite with core-shell-structured CI-TiO2 and MWCNT-PANI exhibits the maximum magnetic and dielectric losses, which yields high RL peaks (>20 dB) tuned within the X-band for layer thickness from 2.5 to 3.5 mm. Particularly for thickness from 2.85 to 3 mm, this quarter-wavelength absorber displays the broadband operation potential as RL values larger than 10 dB can be achieved throughout the X-band.