Browsing by Author "Kilic, Veli Tayfun"

Now showing 1 - 11 of 11

Citation - WoS: 7
Citation - Scopus: 8
Triple Band Diamond-Shaped Polarization Insensitive Plasmonic Nano Emitter for Thermal Camouflage and Radiative Cooling
(Springer, 2024) Sanli, Atif Kerem; Tabaru, Timucin Emre; Kilic, Veli Tayfun
This 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.
Citation - WoS: 16
Citation - Scopus: 18
High-Efficiency Flow-Through Induction Heating
(Wiley, 2020) Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi Volkan
This 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.
Citation - WoS: 3
Citation - Scopus: 5
Single and Double Side Comb-Shaped Patch Antenna Design Evolved From Rectangular Shape for Reduced Sized Antenna Applications
(IEEE, 2020) Baydar, Huseyin; Aslan, Melih; Kilic, Veli Tayfun
This 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.
Comb-Shaped Patch Antenna Design Study With Shifted Arms and Asymmetric Architecture Enabling Controlled Resonance Change and Radiation Pattern
(IEEE, 2022) Asian, Melih; Baydar, Huseyin; Kilic, Veli Tayfun
This 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.
Bandwidth Optimization of an Ultra Wide Band Vivaldi Antenna Design with Its Feed Alignment
(2025) Kilic, Veli Tayfun; Güzelkara, Izzet
Tıbbi görüntüleme, gözetleme veya iç mekan lokalizasyonu gibi ultra geniş bant uygulamaları farklı bant genişlikleri gerektirir. Farklı bant genişliği gereksinimleri genellikle anten tasarımı açısından zorluk teşkil etmektedir. Bu çalışmada ultra geniş bant sistemlerine uygun geniş bantlı bir Vivaldi anten sunulmaktadır. Anten, 3 boyutlu bir elektromanyetik simülasyon aracı kullanılarak tasarlanmış ve optimize edilmiştir. Daha sonra mikroşerit beslemenin anten bant genişliği üzerindeki etkisinin araştırıldığı parametrik bir çalışma yapılmıştır. Antenin bant genişliğinin, başka herhangi bir anten parametresini değiştirmeye gerek kalmadan, mikroşerit beslemenin toplam uzunluğu ve konumu değiştirilerek değiştirilebileceği gösterilmiştir.
Citation - WoS: 2
Citation - Scopus: 2
Crown Shaped Edge Multiband Antenna Design for 5G and X-Band Applications
(Springer, 2023) Hakanoglu, Baris Gurcan; Kilic, Veli Tayfun; Altindis, Fatih; Turkmen, Mustafa
Nowadays 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.
Study on Single Sided Comb Shaped Patch Antennas With Arm Rotation Allowing Resonant Frequency Shift and Pattern Pivoting Adaptable for Sensing Operations
(Pamukkale Univ, 2025) Sanlier, Saban Duran; Tosun, Huseyin; Kilic, Veli Tayfun
In this paper single sided comb shaped patch antennas having different number of arms with various arm rotations are reported. With simulations S11 parameter changes and the far-field radiation patterns of the antennas are calculated. Results show that the first and the second resonances of the designed antennas shift to higher frequencies and their patterns pivot in certain directions as the antenna arms rotate. Among the designed antennas, the antennas having three arms on the side with different arm rotations are manufactured, too. Measured Sii parameter change results agree well with the simulation results. The findings indicate that the designed antennas are promising for size critical systems as well as sensing operations.
Study 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) Aslan, Melih; Sik, Kaan; Güzelkara, Izzet; Özdür, Ibrahim Tuna; Kilic, Veli Tayfun
In 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.
Semi Analytical Study and Calculation of Magnetic Flux Density Created by Rectangularly Shaped Planar Coils With Rounded Corners
(Springer int Publ Ag, 2025) Kilic, Veli Tayfun; Kavuncu, Umut
In 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.
Citation - WoS: 12
Citation - Scopus: 12
All-Surface Induction Heating With High Efficiency and Space Invariance Enabled by Arraying Squircle Coils in Square Lattice
(IEEE-Inst Electrical Electronics Engineers Inc, 2018) Kilic, Veli Tayfun; Unal, Emre; Yilmaz, Namik; Demir, Hilmi Volkan
This paper reports an all-surface induction heating system that enables efficient heating at a constant speed all over the surface independent of the specific location on the surface. In the proposed induction system, squircle coils are placed tangentially in a two-dimensional square lattice as opposed to commonly used hexagonal packing. As a proof-of-concept demonstration, a simple model setup was constructed using a 3 x 3 coil array along with a steel plate to be inductively heated. To model surface heating, a set of six locations for the plate was designated considering symmetry points. For all of these cases, power dissipated by the system and the plate's transient heating were recorded. Independent from the specific plate position, almost equal heating speeds were measured for the similar levels of dissipated energies in the system. Using full three-dimensional electromagnetic solutions, the experimental results were also verified. The findings indicate that the proposed system is proved to enable energy efficient space-invariant heating in all-surface induction hobs.
Microstrip Stub Filter Design with Enhanced Performance Inspired by SIW Structures Operating at 1.93 GHz GSMBand
(Gazi Univ, 2025) Tosun, Huseyin; Yentur, Abdulkadir; Kilic, Veli Tayfun
This paper reports a microstrip stub filter design operating at 1.93 GHz GSM band with enhanced performance inspired by SIW structures. In the designed filter additional vias are placed around the microstrip lines to enhance the encasing of the electromagnetic fields while propagating through the filter to develop the filter performance. The filter was examined with electromagnetic simulations for various numbers of vias and different via to microstrip line distances. Results show that the maximum transmission coefficient (S21 parameter) magnitude value reached in the pass band of the filter increases with the number of the vias and as the vias get closer to the lines. On the other hand, when the via number increases and the space between them and the lines narrows, the frequency at which the maximum S21 value is attained shifts to lower frequencies. The designed filters were manufactured, too. Results obtained in the measurements agree well with the simulation results. Additionally, a receiver system operating at 1.93 GHz band was constructed. System experiments were carried out with the constructed prototype for the manufactured filters. Results show that a greater signal level in the filter pass band is achieved and unwanted signals outside the filter pass band are suppressed more in the system where the filter with vias is used instead of the filter without any additional via. The findings indicate that the designed filters inspired by SIW structures are promising for applications requiring high signal quality.