Functionally Graded Tunable Microwave Absorber with Graphene-Augmented Alumina Nanofibers
| Autor: | Ali Saffar Shamshirgar, José F. Fernández, Maarit Karppinen, Girish C. Tewari, Roman Ivanov, Irina Hussainova, Rocio Estefania Rojas Hernandez |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Graphene Terahertz radiation Percolation threshold 02 engineering and technology Dielectric 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention law Nanofiber Electromagnetic shielding General Materials Science Composite material 0210 nano-technology Absorption (electromagnetic radiation) Microwave |
| Zdroj: | ACS Applied Materials & Interfaces. 13:21613-21625 |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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