Performance of radar absorbing nanocomposites by waveguide measurements

Abstract

Sol-gel synthesis has been investigated in order to produce stoichiometric compositions of Ba 3 Co 2 Fe 24 O 41 (Co 2 Z) at lower calcination temperatures, using citric acid as quelant complex. Using this method, Co 2 Z ferrite could be synthesized at 950 °C, about 400 °C lower than that of conventional method. Nanocomposites (80:20% weight) of this ferrite with polychloroprene (CR) were obtained for the microwave absorption measurements by mixing, molding and curing mixtures of Ba 3 Co 2 Fe 24 O 41 powders with polychloroprene and the additives of vulcanization. The microwave absorption measurements was carried out using the Transmission/Reflection method for the S and X-Ku bands and showed the best performance as Radar Absorber Material (RAM) in 8.0-16.0 GHz range. Thus, the material can be used by reducing the radar signature of the Brazilian Frigates' superstructures.

Effect of Polyvinyl Pyrrolidone Dosage on Barium Ferrite Fibers via Electrospinning

“…As it is known, the absorbing characteristics of the materials depend on the frequency, layer thickness, complex permittivity (ε*= ε'-jε''), and complex permeability (µ*= µ'-jµ''). To investigate the microwave absorption properties of ferrite-polymer, coaxial sample with outer diameter 7 mm, inner diameter 3 mm and thickness of 2 mm was prepared by suppressing mixture of the fibers made by add 14% PVP in its precursor solution and paraffin wax with mass ratio 3:7, and then investigate the complex permittivity and complex magnetic permeability with vector network analyzer ( VNA ) [26]. Fig.…”

Effect of Reaction Time on the Coercivity of Barium Ferrite Synthesized by Hydrothermal Process

“…Therefore, the barium ferrites with c-plane anisotropy can be good candidates for electromagnetic absorbing. [11][12][13] In order to obtain the barium ferrites with suitable saturation magnetization and coercivity, several methods have been used to prepare barium ferrite, such as co-precipitation, sol-gel synthesis, salt-melt method and hydrothermal synthesis. With the development of nanotechnology in recent years, the hydrothermal method has attracted more attention for the preparation of nanoscale barium ferrite.…”