Yazar "Duman, M." seçeneğine göre listele

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    Design and Frequency Characterization of a Rose Antenna Produced with 3D Printing
    (Institute of Electrical and Electronics Engineers Inc., 2023) Tanaydin, Y.S.; Duman, M.
    Antennas are devices used to receive or transmit electromagnetic waves. Antennas can be designed in different shapes for various purposes. Additionally, the radiation patterns of antennas can vary. The radiation pattern indicates how strong the antenna is in a particular direction. Changes in parameters such as the overall operating frequency and input reflection can be observed depending on the shapes and manufacturing materials of the antenna. In recent times, 3D printers have been used for practical antenna production. In this study, the crown petals of a rose were drawn using the AutoCAD program. After obtaining a hard PLA print from a 3D printer, the petals were covered with aluminum tape to provide conductivity. The antenna design, transformed into a 3D rose pattern, was given its final natural antenna appearance by soldering an SMA connector. The antenna's usability within specific frequency bands was discussed through measurements of the S11 parameter using the Nano VNA V2 plus 4 measurement device. © 2023 IEEE.
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    Low noise amplifier design for hidden wireless lan applications using band pass filter with geometric mean prototype element values
    (Yildiz Technical University, 2024) Duman, M.
    Detection and perception problems may occur when the amplitude level of some signals that need to be received and detected is weak. Information that is requested to be kept confidential or not shared with other units is always available in the environment as wireless electromagnetic (EM) waves. Detection can only be made with the appropriate method. Thermal radiation emitted by objects that are intended to be hidden under clothing can also be given as an example. The signal level of these EM waves is very low. In this case, low noise amplifier (LNA) circuits are used to increase such values to a measurable level by network analyzer. In this study, a design with 17.19 dB gain for WLAN applications is made using BL011 LNA chip gathered from BeRex company with a 3rd order band pass filter (BPF) at 2.4 GHz center frequency, it has 200 MHz band width (BW) and 50 ohm characteristic impedance. An innovation has been introduced to design BPF as using the geometric mean prototype element values (PEV) by the help of geometric mean of 4 known techniques: Butterworth, Chebyshev (0.5 dB ripple), Bessel and Gauss (to 12 dB) normalized table values. According to the researches, the BPF circuit created by the geometric averaging method with the BL011 LNA chip has never been used to detect hidden EM signals in the WLAN band. Finally, the proposed BPF circuit is 2 in total, one at the input and one at the output; LNA circuit designed by using BL011 module and impedance matching circuit, a total of 3 consecutively connected and combined systems are formed. The proposed full system has the merits of compactness, good input reflection coefficient and good S21, gain characteristic. © 2024 Yildiz Technical University. All rights reserved.
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    Prevention of Electromagnetic Impurities by Electromagnetics Intelligence
    (Springer Science and Business Media Deutschland GmbH, 2021) Duman, M.
    Nowadays, electromagnetic pollution has an increasing rate. 4G and 5G battles of base stations, 3G, GPRS and radio broadcasts, incredible increase in bluetooth modules, the huge volume of electromagnetic waves generated by wireless communication while talking about smart systems and IOT, infrared systems, NFC, wireless internet networks. Even if it has not been proven that they cause human health or diseases such as infertility, why should we not work to minimize this pollution? Why not protect especially our children from such factors? We may want to take advantage of these important wireless blessings of technology despite electromagnetic impurities, but it would be more appropriate to prevent our children from being exposed to these impurities, at least in some time periods, such as sleep. Within this study; preventing electromagnetic waves from reaching children’s beds, car seats, playgrounds; measuring the frequency and amplitude values of the waves, followed by automatic generation or selection of band stop filters will be done with frequency selective surface analysis method according to these values by artificial intelligence. The decision of preventing which of the transmissions measured with the help of frequency meters and computer programs will be made by artificial intelligence, and then the information such as which electromagnetic waves are propagated more during which hours will be obtained by electromagnetics intelligence to prevent the impurities. According to the information obtained, the use of band stop filters in various fields may become more common. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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    Review and Design of a Simple 60 GHz Microstrip Antenna for Enhanced 5G Performance
    (Natl Inst Science Communication-Niscair, 2024) Duman, M.
    The emergence of 5G technology has drawn the attention of researchers to the 60 GHz frequency spectrum which provides a wide bandwidth and massive data transfer with high data rates and low latency communication. Wireless systems utilizing 60 GHz enable multiantenna systems and several applications on the contrary to lower carrier frequencies. In this study, the prominence of the 60 GHz frequency is explained with references to various studies, information from web pages, and publications. While offering faster data transfer compared to 4G and Wi-Fi signals, unfortunately, it has a shorter range. The effectiveness of 60 GHz is only applicable for unobstructed distances; the range decreases significantly in the presence of obstacles. Attenuation is another important issue, because of the oxygen at 60 GHz frequency, most of the signal is absorbed, so it is thought that it will be preferred more for indoor applications and wireless office communication. Technologic progresses continue rapidly, perhaps by increasing the number of sectors of base stations, beam forming technology or mesh networking between electronic devices the long distance issue can also be eliminated. In this study, an antenna design was also given after the review of 60 GHz and 5G, as a research side and it had -8.7 dB S11 value and 5.54 dBi gain. The designed micro strip antenna, particularly at 60 GHz, holds significant potential for various applications and contributes to the advancement of future communication technologies. Some potential applications include: 5G, wireless local area networks, indoor wireless communications, short range communication links, point-to-point and point-tomultipoint links, IoT, advancement in mm wave technology and so on with high data rate.