Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Sensitive Hybrid Plasmonic Refractive Index Sensor Based on Ag Cross-Grating Nanoantenna and Au Quantum Dot upon SiO2 Nanowire(IOP Publishing Ltd, 2026-04-03) Sanli, Atif Kerem; Kilic, Veli Tayfun; Tabaru, Timucin EmreThis study presents a distinctive hybrid plasmonic sensor architecture combining a silver (Ag) cross-shaped nanoantenna with a gold (Au) quantum dot (QD) for enhanced refractive index sensing applications. The structure consists of a silicon dioxide (SiO2) substrate and a cylindrically shaped SiO2 wire on it, topped with a silicon nitride (Si3N4) dielectric layer and an Ag cross grating, with an Au QD positioned at the center. Using free and open source 3D Finite-Difference Time-Domain (FDTD) simulations, exceptional electric field enhancement at the resonant wavelength of approximately 639-667 nm is demonstrated. The optimized structure achieves remarkable quality factors (Q-factors) exceeding 267 for biological media, representing among the highest reported values for plasmonic sensing structures. Unlike conventional red-shift sensors, our design exhibits a distinctive blue-shift sensing behavior arising from hybrid plasmonic mode coupling, achieving sensitivities ranging from 190 to 344 nm RIU-1 for various analytes, including water, blood, PDMS, body fat, ethanol, and glass. The ultrasharp resonances (FWHM similar to 2.3 nm) combined with intense field enhancement make this design highly suitable for biosensing applications.Article Wireless Communication System Design for Point Machine Detection and Monitoring in Railways(Springer, 2026-03-09) Talu, Burak; Cetin, Fatih; Kilic, Veli Tayfun; Elden, Burakhan; Sanlier, Saban DuranThis paper reports on a wireless communication system that is used in railways to instantly detect and continuously monitor point machine positions. Also, with the system the position information is transmitted wirelessly to a train driver. The designed system is composed of TX and RX units. It has a compact structure and is fully modular. The TX unit of the system is placed near the railway point machines and the RX unit is located on a train. The designed system was constructed, and measurements were obtained on-site. Results show that the system point machine position data were accurately transmitted at 1350 m range which is much longer than the safe braking distance of a train. In addition, the measured 1 s data sampling time of the system allows the driver to continuously monitor current RPM positions as well as state changes. The maximum delay was found to be 3 s in the limit range of the communication. It is found that the system has a low power consumption and the designed system can work for long hours. The findings indicate that the designed wireless communication system has a high potential to be used in railways to prevent accidents and contribute to the overall safety and efficiency of operations.Article Citation - WoS: 10Citation - Scopus: 10Triple Band Diamond-Shaped Polarization Insensitive Plasmonic Nano Emitter for Thermal Camouflage and Radiative Cooling(Springer, 2024-05-13) Sanli, Atif Kerem; Tabaru, Timucin Emre; Kilic, Veli TayfunThis study proposes the design of a novel Metal-Insulator-Metal (MIM) nano-infrared emitter that uses a unique diamond-shaped grating to achieve selective infrared absorption. Diamond-shaped nano emitter (DNE) structure exhibits four narrow resonant peaks within key absorption windows such as short-wave infrared (SWIR) mid-wave infrared (MWIR), alongside with a wide absorption band in the Non-Transmissive Infrared Range (NTIR) for thermal camouflage applications compatible with radiative cooling. Moreover, the proposed DNE is polarization insensitive as it has an in-plane symmetric design. Using the 3D Finite-Difference Time-Domain (FDTD) simulations, we demonstrate the nanoantenna's superior performance characterized by its high absorption rates and tuned effective impedance matching. As of our knowledge, the findings suggest that this is the first time that a MIM structure achieved multiple narrow resonance peaks, located in SWIR and MWIR simultaneously, with a wide absorption range in NTIR. Represented DNE stands as a significant innovation in the field of stealth technology, providing a tunable, high-efficiency solution for managing and controlling thermal emissions across diverse applications.Article Citation - WoS: 1Citation - Scopus: 1Study of Helical Antenna Endowing Short Wire Length and Compact Structure for High-Frequency Operations and Its Exclusive Manufacturing Process(Tubitak Scientific & Technological Research Council Turkey, 2023-03-01) Aslan, Melih; Sik, Kaan; Güzelkara, Izzet; Özdür, Ibrahim Tuna; Kilic, Veli TayfunIn this paper a study of a helical antenna resonating at high-frequency (HF) band with a very compact structure is reported. The designed antenna's S11 parameter magnitude change with frequency was calculated for different geometrical parameters. For each case, first, only a single parameter was changed. Then for a fair comparison, multiple parameters were changed simultaneously while the total wire length was set to be constant. Also, shifts in resonance frequencies and variations in -10 dB bandwidths were investigated. Our results show that resonance behaviour changes distinctively with the geometrical parameters and it allows shortening of the antenna wire length. For the designed antenna, the resonances shift to lower frequencies and -10 dB bandwidths around the resonances decrease as the winding wire thickness, number of turns, and turn radius increase. Whereas as the turn spacing increases the resonances shift to higher frequencies and -10 dB bandwidths widen, although the total wire length of the antenna increases. To verify the simulation results, the designed antenna was fabricated with an exclusive manufacturing process and characterized. The measurement results are in good agreement with the simulation results. It demonstrates the feasibility of the proposed manufacturing technique, which is new in the literature and enables accurate and rigid antenna fabrication with simple and low-cost steps.Conference Object Citation - WoS: 3Citation - Scopus: 6Single and Double Side Comb-Shaped Patch Antenna Design Evolved From Rectangular Shape for Reduced Sized Antenna Applications(IEEE, 2020-11-18) Baydar, Huseyin; Aslan, Melih; Kilic, Veli TayfunThis paper reports single and double side comb-shaped patch antennas to be used in reduced-sized antenna applications. The proposed antenna designs are evolved from regular rectangular shape antennas. The designed single and double side comb-shaped antennas were investigated in a complete set of study together with the rectangular shape antenna that resonates at 5 GHz frequency. Reflection coefficient (S-11) parameter of the designed comb-shaped antennas and the rectangular antenna were calculated together with three-dimensional (3D) directivity patterns in simulations for different arm lengths, arm widths, and arm numbers of the comb-shaped antennas. Results show that with the comb-shaped antennas it is possible to shift the resonance frequency of a regular rectangular shape antenna to a frequency lower than its half without enlarging the foot-print area or with the smaller foot-print area. Also, resonance frequency change and peak directivity variations at resonance frequencies of the antennas with geometrical parameters of the antennas were calculated, too. The findings indicate that due to the large number of geometrical parameters that come with the nature of the comb shape, comb-shaped antennas provide more flexibility while constructing an antenna.Article Semi Analytical Study and Calculation of Magnetic Flux Density Created by Rectangularly Shaped Planar Coils With Rounded Corners(Springer int Publ Ag, 2025-04-25) Kilic, Veli Tayfun; Kavuncu, UmutIn this paper, magnetic flux density induced by a rectangularly shaped single-turn planar coil with rounded corners is investigated. Starting from Biot-Savart law analytical derivations are obtained and contributions of straight edges and rounded corners of a coil to a flux density at a point in a three-dimensional space are formulated. In the derived formula the magnetic flux density generated by a coil with rounded corners is expressed as a function of the coil's geometrical parameters including start and end points of the roundings together with the center of the circles that contain arcs at the corners and observation point coordinates. Magnetic flux density distribution of rectangular coils with different sizes and roundings at the corners were calculated on distinct planes by using the derived formula. Also, FEM based electromagnetic simulations and measurements were done for the same coils. The results obtained in the analytical calculations, FEM calculations and measurements are in a good agreement.Article Citation - WoS: 18Citation - Scopus: 20High-Efficiency Flow-Through Induction Heating(Wiley, 2020-08) Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi VolkanThis study reports a newly designed induction heating system for efficient, fast, and safe flow-through heating. The system has a very simple architecture, which is composed of a transmitting coil, an isolating plastic pipe, and an embedded metal shell. Wireless energy transfer from the external coil to the internal metal shell through the pipe is essential for decreasing losses. Also, a large contact surface between a fluid and the immersed shell enables rapid heat transfer. The proposed heating system was systematically investigated for different shell geometries and the results were compared with a commercially available conductive flow-through heating device. As a proof-of-concept demonstration, a prototype of the designed induction heating system was manufactured and the heating measurements were conducted with water. Power transfer efficiency of the prototyped induction heating system was measured to be 97%. The comparative study indicates that such high-efficiency induction flow-through heating system offers a great potential for replacing the conventional conductive heating device used in household applications in which the rapid and compact heating is desired.Article Citation - WoS: 2Citation - Scopus: 2Crown Shaped Edge Multiband Antenna Design for 5G and X-Band Applications(Springer, 2023-06-03) Hakanoglu, Baris Gurcan; Kilic, Veli Tayfun; Altindis, Fatih; Turkmen, MustafaNowadays we are experiencing the fifth-generation (5G) technology with new frequency bands to achieve high broadband speed, minimum latency and more developed end user devices. Due to the different frequency ranges for different applications at 5G bands the antennas should support multiband operation in a compact structure. This paper proposes a new multiband microstrip patch antenna design operating at mid band 5G frequencies and in the X band. The structure of the antenna includes simply loading the top radiating edge with rhombic shaped stubs and slots. This configuration yields the antenna to have resonances at multiple frequencies based on the fact that the stubs and slots affect capacitive and inductive impedances on the lower and higher operating frequencies of the antenna. The unique design enables the antenna to have reasonably high gains at four different bands of 6.76 dBi, 6.47 dBi, 7.76 dBi and 5.51 dBi at 3.34 GHz, 4.61 GHz, 6.01 and 8.02 GHz, respectively. Also, the simulated antenna has been manufactured and measured. The measurement results are in good agreement with the simulation results. The proposed design can be used with many other frequency bands and dielectric materials as well to achieve multiband operation.Conference Object Comb-Shaped Patch Antenna Design Study With Shifted Arms and Asymmetric Architecture Enabling Controlled Resonance Change and Radiation Pattern(IEEE, 2022-07-08) Asian, Melih; Baydar, Huseyin; Kilic, Veli Tayfun; Aslan, MelihThis paper reports comb-shaped patch antennas with asymmetrical geometries having two and three arms on the sides. The proposed geometry is evolved from regular rectangular shaped patch antenna by removing certain parts of the radiator patch and shifting the arms on one side of the antenna. Systematic simulations were obtained with the designed antennas for different arm shifting distances, and changes in resonance behavior and far-field radiation pattern were investigated. Results show that as the arm shifting increases the first and second resonance frequencies of the antennas decrease. Also, it is observed that the radiation occurs with two symmetric beams at the second resonance frequency of the designed antennas with no shift between the arms. However, as the arm shifting is applied the beam on the side of the arms closer to the feeding line gets stronger, whereas the other beam weakens. Obtained plots indicate that the directivity of the antennas have a tendency to increase with the arm shifting while the side lobe level decreases. In addition, results show that the half power beam width of the antenna increases with arm shifting. The simulations were repeated for different arm thicknesses and the same observations were held.