The electromagnetic properties and microwave absorption of mesoporous carbon

Fabrication and electromagnetic properties of novel FeNi alloy-coated flake graphite prepared by electroless plating

“…This phenomenon can be ascribed to following fact: FeNi-FG displays a frequency dispersion behavior, that is, the ε 0 values will gradually decrease as the frequency increases. This frequency dispersion behavior also exists in most carbon materials with different magnetic components [29]. The ε 00 curve respectively presents three fluctuation peaks at 9.7 GHz, 14.7 GHz and 17.5 GHz, and the multi-peak phenomenon can result from the conductance loss and relaxation loss mechanisms.…”

Time-sensitivity for the preparation and microwave absorption properties of core–shell structured Ni/TiO2 composite microspheres

“…Compared with previous reports [26][27][28], such as Fe/ FeAl 2 O 4 coatings deposited by Al/Fe 2 O 3 powders (-11.2 dB) [27] and BaCoTiFe 10 O 19 hexaferrite layers (-15.0 dB) [28], the core-shell Ni/TiO 2 composites possess the features of strong absorption, thin thickness and wide-band. The best microwave absorption capabilities were attributed to the good impedance match [29]. It requires that the complex permittivity is close to the complex permeability to achieve zero-reflection at the front surface of the materials.…”

Electromagnetic and microwave absorption characteristics of PMMA composites filled with a nanoporous resorcinol formaldehyde based carbon aerogel

“…Structural properties, chemical functionality as well as particle size distribution (PSD) are some special intrinsic characteristics having the dominant effect on the electromagnetic properties of these types of absorbents. 4,8,[18][19][20][21] For example, Huang et al 22 investigated the effect of pore texture of sol-gel derived resorcinol-furfural on EM characteristics of the mesoporous carbons. It was concluded that the synthesized porous carbons with a cage-like structure exhibited interesting electromagnetic properties in terms of the real and imaginary parts of the permittivity.…”

“…3,8,24 Moreover, in addition to general absorption mechanisms, multiple reections of microwaves in CAs composites also lead to an additional loss mechanism of EM energy, which is based on the interference of reected waves inside CAs particles. 8,18,22,48,52 In comparison with the typical carbon-based absorbers, depends on synthesis procedure CAs possess pores with different sizes and shapes within their structure, which could provide additional pathway for the absorption of EM waves. 22 Hence, under the above circumstances, preparation of CAs composites with larger particle sizes results in better impedance matching condition under which the EM waves are retract and attenuate when penetrate through the carbon particles.…”