A review and analysis of microwave absorption in polymer composites filled with carbonaceous particles

Design of Carbon Nanotube-Based Broadband Radar Absorber for Ka-Band Frequency Range

“…A great number of investigations show that nanocarbon materials have excellent electromagnetic properties to be used for production of composite materials with controlled electromagnetic properties [10][11][12][13][14]. In the present paper, we use carbon nanotube-based composites to produce an effective broadband absorber for Ka-band region (26-37 GHz).…”

Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range

“…The shielding efficiency (SE) of composites fabricated with different carbonaceous nano-inclusions [4,6] is enhanced with the electrical conductivity, and therefore depends on the nanofiller weight percentage as well as on CVD synthesised CNT flexible sponge with density lower than 0.02 g cm -3 has been found to serve as high performance EMI shielding material without the aid of any polymer infil-tration or impregnation. Due to its extreme lightweight, the specific SE of the CNT-sponge was found to be as high as 1100 dB cm 3 g -1 , having a total SE above 20 dB in the whole 1-18 GHz range, and being able to shield by absorption.…”

“…Since the electrical conductivity of the composites depends on the dispersion degree of the nano-conductive filler [6], SE with values over 20 dB has been normally achieved with high filler loadings (e.g. 20 wt%), a fact that is neither economically desirable nor viable for processing.…”

“…This process could be even more efficient if the conducting fillers are combined with ferromagnetic nanoparticles [5]. Among several possibilities, carbonaceous particles might be able to serve as active microwave absorbers in polymer composites [6].…”

“…In some cases, these foams might have an additional advantage regarding EMI shielding by absorption-dissipation, as reported in MWCNT/polycaprolactone composites [19], in which the reflectivity was efficiently lowered using low CNT volume fractions when compared to solid composites having similar electrical conductivities. This reflection results from the mismatch of impedances at the propagating medium (air)/shield interface; the relative volume of air at the interface lowers the shield surface impedance, thus boosting the wave propagation within the material [6,20].…”