Electromagnetic wave reduction of multiwalled carbon nanotubes (MWCNT) mixed nanometer CoFe2O4 at higher frequency range

Abstract

Traditional granular electromagnetic wave absorbers such as spinel ferrites are well known because of its high saturation magnetization and electrical resistivity. However, the application of ferrite absorbent as an electromagnetic wave absorber is restricted by their increased in density and poor environmental stability. Thus, multiwalled carbon nanotubes (MWCNTs) were introduced to enhance the electromagnetic wave absorbing performances. Different weight percentages of MWCNTs (0.5 wt%, 2 wt% and 4 wt%) were mixed with nanometer-size CoFe2O4 and being used as fillers (60 wt%), further incorporated into epoxy resin as polymer matrix (40 wt%). The reflectivity and morphological study of the prepared samples were measured at X and Ku-band (8 – 18 GHz). The results reveal that varying the amount of MWCNT content has influence the performance of the processed electromagnetic wave absorber. The reflection loss peak shifted towards a lower frequency for thickness of 1 mm, 2 mm and 3 mm as the MWCNT content increased. The MWCNTs content was 2 wt% for a thickness of 3 mm, resulting in a reflection loss of −28 dB, refers to the largest reflection loss achieved at 9 GHz.