Browsing by Author "Kiliç, Veli Tayfun"

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Strand Wire Winding Method in a Solenoidal Coil With Limited Geometry for Good Impedance Matching
(Polska Akademia Nauk, 2023) Kiliç, Veli Tayfun
This paper reports a new strand wire winding method in a solenoidal coil with limited geometry that enables good impedance matching. In the proposed method strand wires are wound layer-by-layer on top of each other allowing one to set equivalent inductance and resistance of the coil to desired values while obtaining dense magnetic flux and high current carrying capacity. As a proof-of-concept demonstration, simple model setups were constructed with solenoidal coils composed of copper wire strands wound according to the proposed method, and a plastic pipe. The measurements were repeated with a metal shell placed inside the coil to model a complete heating system. System inductance and resistance were measured at two different frequencies. The results show that with the new winding method it is possible to increase a coil’s turn number and the number of strand layers composed by the coil. Also, adding and removing strand layers in the proposed coil architectures enable inductance and resistance values to decrease and increase, respectively, in a controlled way. To understand changes of system parameters, simulations were also performed. The calculated inductance and resistance values in the simulations agree well with the measurement results and magnetic flux distribution created in the system demonstrates the changes. © 2023 Elsevier B.V., All rights reserved.
Design of a Portable DF System With Simple and Compact Structure Operating at 875 MHZ GSM Band
(Institute of Electrical and Electronics Engineers Inc., 2021) Uludag, Mert; Ozoksuzkaya, Ali; Kiliç, Veli Tayfun
This paper reports a portable GSM direction finding system operating at 875 MHz frequency band with simple and compact structure. In the system, array of receiver antennas are placed together with other RF components including amplifiers, power dividers, phase comparators, an analog to digital converter and a processor unit. With help of the developed algorithm phase comparison between the receiver antenna channels is obtained and angle estimation is done. The developed algorithm was first run on a constructed system test setup that involves a digital oscilloscope connected to the receiver antennas in a laboratory environment. Later, the digital oscilloscope in the test setup was replaced with the RF components mentioned above such that a portable receiver system with compact structure was obtained. Direction finding experiments were repeated with the designed portable receiver system in the laboratory and in open space. Results show that with the designed system angle of a transmitter is found very accurately such that the maximum angle error between the estimated and the exact angle values of the transmitter antenna was found to be equal to 3.5° in the open space experiments for the transmitter antenna positioned at an angle between -60° and 60° on the horizontal plane same with the receiver antennas. Also, it is observed that the difference between the estimated and the exact angle values has an increasing trend with the exact angle absolute value. The findings indicate that the designed portable direction finding system is promising to be used for applications requiring accurate angle estimation of GSM signals. © 2022 Elsevier B.V., All rights reserved.
Citation - WoS: 2
Citation - Scopus: 4
Magnetic Field Calculation of Square Coils Having Rounded Corners
(Institute of Electrical and Electronics Engineers Inc., 2019) Erman, Muhammed Furkan; Kiliç, Veli Tayfun
There are differently shaped coils for induction heating used in industry such as circular, and square coils. While producing square-like shaped coils, it is unavoidable to face production difficulties due to the sharp corners. At the end of the production, instead of square-like shape, edges are flat and corners are rounded shape coil which is called squircle coil is produced. This paper will discuss how these rounded corners effect the magnetic field at the center of the coil by deriving missed formulas in the literature, and prove the results by comparing with the results of generally known formulas. © 2020 Elsevier B.V., All rights reserved.
Gain Enhancement of a mmWave Patch Antenna Array Having Limited Number of Input Ports
(Institute of Electrical and Electronics Engineers Inc., 2024) Keskin, Mehmet Ziya; Yentur, Abdulkadir; Ozdur, Ibrahim T.; Kiliç, Veli Tayfun
mmWave sensors are rapidly being used in various fields due to their low power consumption, compact size, and cost-effectiveness, particularly for applications like target detection and tracking. This study investigates the gain enhancement of a patch antenna array operating in the mmWave frequency band of 76 GHz - 81 GHz, where commercial single-chip integrated circuits are available. We analyze the S-parameters and radiation patterns of a reference antenna in detail, comparing simulation results with experimental measurements to ensure accuracy. Acknowledging the challenges posed by mmWave patch antennas, we propose a straightforward method to enhance peak gain while preserving the capabilities of the commercial patch structure. Specifically, by twinning one of the input port signals using a power divider, we increase the number of elements in the array without altering the number of input ports. Our findings suggest that this technique can increase the peak gain by 1.3 dB and narrow the beam by 4°, resulting in practical benefits such as enhanced target detection range and accuracy in radar applications while mostly preserving the functioning of the system. © 2025 Elsevier B.V., All rights reserved.