Abstract
Graphene is currently attracting attention for radiation absorption particularly at gigahertz and terahertz frequencies. In this work, composites formed by graphene-augmented γ-Al2O3 nanofibers embedded into the α-Al2O3 matrix are tested for X-band absorption efficiency. Composites with 15 and 25 wt % of graphene fillers with shielding effectiveness (SE) of 38 and 45 dB, respectively, show a high reflection coefficient, while around the electrical percolation threshold (∼1 wt %), an SE of 10 dB was achieved. Furthermore, based on the dielectric data obtained for varying fractions of graphene-/γ-Al2O3-added fillers, a functionally graded multilayer is constructed to maximize the device efficiency. The fabricated multilayer offers the highest absorption efficiency of 99.99% at ∼9.6 GHz and a full X-band absorption of >90% employing five lossy layers of 1-3-5-15 and 25 wt % of graphene/γ-Al2O3 fillers. The results prove a remarkable potential of the fillers and various multilayer designs for broad-band and frequency-specific microwave absorbers.
Original language | English |
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Pages (from-to) | 21613–21625 |
Number of pages | 13 |
Journal | ACS Applied Materials and Interfaces |
Volume | 13 |
Issue number | 18 |
Early online date | 27 Apr 2021 |
DOIs | |
Publication status | Published - 12 May 2021 |
MoE publication type | A1 Journal article-refereed |
Keywords
- alumina
- graphene
- hybrid nanofibers
- impedance matching
- microwave absorption
- multilayer structure
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