Microwave absorbing properties of a radar absorbing structure composed of carbon nanotube papers/glass fabric composites

Abstract

In this study, carbon nanotube papers were employed in fabricating thin and broadband radar absorbing structures (RAS). Different concentrations of the CNT papers have been made by using a vacuum filtration method, with 20 × 20 cm in size and 21‐27 μm in thickness. An epoxy resin was added into the CNT paper and then cured to become a composite with 1‐5 wt.% of CNTs and 83‐309 μm in thickness. The complex permittivity and permeability (ε′, ε″, μ′, μ″) of the CNT paper composites were measured using the transmission/reflection method in the frequency range of 2‐18 GHz. The results reveal that the real (ε′) and imaginary (ε″) parts of the complex permittivity are increased with the CNT concentration. The ε′ of 5 wt.% CNT sample reaches 323 at 2 GHz and then decreases to 49.0 at 18 GHz. The ε″ reaches 321 at 2 GHz and decreases to 26.0 at 18 GHz. The CNT paper composite combined with a glass fabric composite used for a dielectric spacer is fabricated for an innovative RAS and the reflection loss is measured using the arch method in a microwave anechoic chamber. The results show that the 5 wt.% CNT paper composite/glass fabric composite absorbers attain maximum reflection loss of −13.3 dB at 12.0 GHz, −13.8 dB at 10.0 GHz, and −16.0 dB at 7.5 GHz for spacer thickness of 1.5, 2.0, and 3.0 mm, respectively.

Morphological, mechanical, and electromagnetic interference shielding effectiveness characteristics of glass fiber/epoxy resin/MWCNT buckypaper composites

“…On the other hand, when the amount of MWCNT increases in composites (to 3 buckypapers), an increase of ε' can be observed (Figure 3). These results are in agreement with those previously reported in the literature 13,43,44 . GF/EP/BP/PF‐3 and GF/EP/BP/RPF‐3 laminates show large storage capacity (real component ε') in the range of 9.90 to 22.21 at X‐band, and from 4.71 to 16.23 at Ku‐band.…”

Sustainable Development of Carbon Nanocomposites: Synthesis and Classification for Environmental Remediation

“…CNTs possess special optical intrinsic properties such as near-infrared photoluminescence (NIR) [167]. The biocompatibility and biodegradability were increased by turning the layer of pristine CNTs into hydrophilic f-CNTs [168]. Such biosensors analyse a broad variety of genetic markers of cancer by conjugating DNA or proteins, peptides, enzymes [169], and electrochemical biosensors for the early diagnosis of genetic markers of cancer [170].…”

Cyanate Ester—Epoxy Blends for Structural and Functional Composites

“…But since EP lacks thermal stability, in addition to its poor moisture resistance, they are blended with CE. Further enhancement in dielectric and structural aspects of composite has been accomplished by incorporating fillers such as carbon black, , graphene nanosheets, , graphene oxide, CNTs, carbon veils, and continuous glass fibers , in the polymeric matrix.…”