Development of Low-Frequency CI/BFO Composite Microwave Absorbing Material

A significant effort has lately been made to produce unique nanomaterial composites showing excellent microwave absorption, thin thickness, and wide bandwidth. Many radars' operating frequency ranges have been expanded to the L-band and S-band, however, the microwave absorbing materials exhibiting excellent microwave absorption in low-frequency range have been rarely reported. Thus, in this study, an attempt to develop a broadband microwave absorber working in low-frequency band has been made. For this purpose, the CI/BFO composite is prepared using a simple and scalable high-energy ball milling process; the milling of 2 wt% of barium ferrite nanoparticles and CI was carried out for 15 hours. The CI/BFO composite's complex permittivity and permeability have been measured across the frequency range of 0.5 to 14 GHz. The coaxial transmission-reflection method has been used to calculate the microwave absorption properties of the material. The enhanced microwave absorption bandwidth of 7.35 GHz (1.63-8.98) was obtained for CI/BFO 2% -15h sample with the coating thickness of 3.0 mm. Importantly, because the fabrication procedure employed here is rather simple, the as-prepared CI/BFO composite can be considered to be used as a candidate in the absorption of low-frequency microwaves.