Browsing by Author "Tütüncü, B."

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Design and Analysis of Highly Efficient Microwave Absorber for 5g Applications
(Institute of Electrical and Electronics Engineers Inc., 2024) Türktam, U.; Tütüncü, B.
This study presents the design of a highly efficient microwave absorber on an FR-4 substrate measuring 48x66x1.5 mm3. Design and simulation were conducted using CST STUDIO, with several parametric studies aimed at achieving increased absorption within the desired frequency band. Alterations to the geometric shape constituted the stages of absorber refinement, with simulation values analyzed to assess absorber efficiency at each stage. Throughout the four analysis steps, the absorption was obtained at three different frequency values covering the n77 and n78 5G bands, with the highest absorption observed at 3.8 GHz. In conclusion, in the final geometric configuration, electromagnetic wave absorption percentages were determined as 97.3%, 98.04%, and 97.8% at frequencies of 3.7 GHz, 3.8 GHz, and 3.9 GHz, respectively. © 2024 IEEE.
Dual-Band Microstrip Antenna for Gps L1 and L2 Applications
(Institute of Electrical and Electronics Engineers Inc., 2024) Karakiş, B.; Tütüncü, B.
This study presents the design of a dual-band microstrip antenna specifically engineered for operation within the GPS L1 (1.575 GHz) and L2 (1.227 GHz) frequency bands. The proposed antenna demonstrates optimal performance characteristics, rendering it well-suited for applications that require precise navigation capabilities. The design process was conducted using CST Microwave Studio, focusing on the optimization of the antenna's shape and dimensions to achieve the desired return loss and gain across both frequency bands. The substrate selected for this antenna is FR4, with an optimal thickness of 1.6 mm. The antenna achieved gains of 5.38 dBi at the GPS L1 frequency and 5. 33 dBi at the GPS L2 frequency. Through a stepwise design approach, which included the incorporation of omega-shaped slots, the antenna's return loss was significantly improved, reaching values of -30 dB at L1 and -35 dB at L 2. These results validate the antenna's suitability for GPS applications, providing high gain and low return loss, thereby enhancing signal reception and precision in GPS-based systems. © 2024 IEEE.
Dual-Band Polarization-Insensitive High-Efficiency Metamaterial Absorber for Ism-Band Biomedical Applications
(Springer, 2024) Tütüncü, B.; Altıntaş, Y.
The design, optimization, fabrication, and measurement of a dual-band, metamaterial-based polarization-insensitive, high-efficiency signal absorber in the 2.38–5.81 GHz frequency range of the ISM band is presented. The primary objective of this study is to design a microstrip absorber that is compact and simple, and therefore provides low fabrication errors and ease of integration. To achieve this goal, a comprehensive investigation is conducted to optimize the patch geometry to exhibit metamaterial characteristics, thus harnessing the signal-focusing capability. Another goal of this study was to achieve polarization independence, which poses an additional challenge. This was achieved simultaneously by achieving overlapping structural symmetry with the metamaterial properties. Additionally, various design parameters, such as substrate thickness and material selection, are explored, and their optimum values are determined through numerous simulation studies. Accordingly, the proposed absorber is fabricated based on the optimum simulated values. The measurement and simulation results are in good agreement with each other. Finally, the proposed structure is compared with other metamaterial absorbers operating in the same frequency range reported in the literature, presented in a comparative table, and its performance superiority is demonstrated. © 2023, The Minerals, Metals & Materials Society.