Browsing by Author "Colak, Bektas"

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Absorbing Properties and Structural Design of Pvb/Fe3o4 Nanocomposite
(Elsevier Science Sa, 2019) Akinay, Yuksel; Hayat, Fatih; Colak, Bektas
Recently, a wide range of studies has been carried out on microwave absorber composites for use in telecommunications, electromagnetic pollution, stealth technology, and other applications. In this study, the microwave absorption properties of polyvinyl butyral (PVB)/polyaniline (PAM) coated-Fe3O4 (COM1) and PVB/Fe3O4 (COM2) nanocomposites with single and double layer were investigated in the 1-14 GHz for different thickness (t(m)) of composites. XRD, FT-IR, TEM, and SEM were used to determine the structure properties of the composites. The Coaxial transmission line method was used to obtain permittivity (epsilon', epsilon '') and permeability (mu', mu '')parameters of the composites. The reflection loss of the single and multilayers of different thicknesses was calculated. It was figured out that the higher value of reflection loss (R-L) (-51.5 dB at 11.9 GHz) was obtained with COM2 composite. However, using PANI has provided a wider absorption range in COM1 composites. It was found that multilayer composites (COM4) provide broadband absorption compared to COM2 and double-layer design (COM3).
The Electromagnetic Wave Absorption Properties of Woven Glass Fiber Composites Filled With Sb2o3 and Sno2 Nanoparticles Doped Mica Pigments
(Wiley, 2022) Akinay, Yuksel; Colak, Bektas; Turan, Muhammet Emre; Akkus, Ihsan Nuri; Kazici, Hilal Celik; Kizilcay, Abdullah Oguz
In this study, the electromagnetic wave absorption properties of woven glass fiber reinforced epoxy composites with Sb2O3 and SnO2 nanoparticles doped mica pigments were investigated. Herein, we synthesized SnO2/mica, Sb2O3/mica, and Sb2O3:SnO2/mica pigments using the sol-gel method. Subsequently, mica pigments filled glass fiber/epoxy composite panels were fabricated with a vacuum assisted resin mold. The phase, crystal, and morphological examinations of particles confirm the deposition of SnO2 and Sb2O3 nanoparticles on the mica surfaces. The electromagnetic wave absorption properties of samples were measured using the S parameters and obtained dielectric data. Sb2O3:SnO2/mica particles display higher complex permittivity and dielectric loss values due to the strong interfacial polarization between conductive nano metal-oxide shells and mica surfaces. According to the calculated reflection loss values, Sb2O3:SnO2/mica particles exhibit superior electromagnetic wave absorption performance with a minimum reflection loss of -25.62 dB for 2.4 mm thicknesses with effective bandwidth between 9.3 and 12.4 GHz. The S parameters of the prepared structural composites with the size of 30 cm x 30 cm x 3 mm was determined by the free-space technique using the transmission line technique. According to the S-12 parameters, filled glass fiber/epoxy composite containing 25 wt% Sb2O3:SnO2/mica show a minimum reflection loss of -20.426 dB at 8.2 GHz with effective bandwidth between 8.2 and 9.67 GHz. These results indicate that Sb2O3:SnO2/mica-filled fiber/epoxy composite is an excellent candidate for the practical application of electromagnetic wave absorbers.
Recent Progress of Electromagnetic Wave Absorbers: a Systematic Review and Bibliometric Approach
(Keai Publishing Ltd, 2023) Akinay, Yuksel; Gunes, Umit; Colak, Bektas; Cetin, Tayfun
The electromagnetic wave absorption capabilities of an absorber depend on its dielectric and magnetic components, which determine its interfacial polarization, conductivity loss, magnetic loss, and other such mechanisms. In this study, a comprehensive review of the electromagnetic wave and material interaction was conducted. Moreover, for a better understanding of the trends and evolutionary developments in the study of the electromagnetic wave absorber, 23300 documents dated between 1990 and 2020 were examined, which were obtained from Scopus using the keywords of "electromagnetic wave absorption " and "microwave absorption ". The data search in Scopus was conducted using the related keywords in the search bar for titles and abstracts. These results demonstrate that the majority of research regarding electromagnetic wave absorbers was conducted in China, which was followed by the United States. The number of published documents regarding the electromagnetic wave absorption field significantly increased between 1990 and 2020; these documents were mostly published as journal articles. With respect to the journal activity, the most productive journal was the "Journal of Alloys and Compounds ", with a total of 592 articles. In addition, graphene and titanium dioxide were determined to be the materials that were most studied in the field of electromagnetic wave absorption.