Yazar "Celik, Ali Recai" seçeneğine göre listele

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    Development of an ultra-wideband, stable and high-directive monopole disc antenna for radar-based microwave imaging of breast cancer
    (Taylor & Francis Inc, 2018) Celik, Ali Recai; Kurt, Muhammed Bahaddin
    Radar-based ultra-wideband (UWB) microwave imaging (MI) system has recently attracted considerable attention for detection of breast cancer at early stage. A key component of the system is the sensor (antenna) that is used to radiate and receive the UWB pulses. In this study, a compact-size, UWB, directive, and microstrip-fed planar circular disc monopole antenna (PCDMA) with modified L-shaped ground plane for the radar-based UWB MI system is developed. Analysis and the performance optimization of the proposed antenna are performed by HFSS software. In the development process of the antenna design, some modifications such as adjusting feed point, adding parasitic element, slot, notches are made on the conventional PCDMA to improve the bandwidth, directivity and half-power beamwidth (HPBW) of the antenna. After obtaining the optimum parameters, the proposed antenna is fabricated and then tested by using Vector Network Analyser. Impedance bandwidth of the designed antenna covers the broad frequency range of 3-10 GHz (108%) for Return Loss < -10 dB. The good stability of the directional radiation patterns is obtained in the 3-10 GHz. The direction of the maximum radiation moves from 32 degrees to 54 degrees and HPBW decreases from 56 degrees to 30 degrees through the frequency band. The directivity changes between 6.2 and 9.4 dB in the 3-10 GHz. Results confirm that the proposed antenna is suitable for using in radar-based UWB MI of the breast cancer.
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    Öğe
    Image Processing on Field Programmable Gate Arrays
    (Ieee, 2015) Celik, Ali Recai
    At present, the relevancy to image processing is increasing and applications of image processing are developing. Also Field Programmable Gate Arrays (FPGA) is gaining in popularity nowadays. FPGAs are strong in parallel computation and then can work too fast. Because of these advantages, they are preferred in applications which has complex calculation and needs high speed. In this work, basic image processing applications were implemented on FPGA hardware. Real-time motion video was used for these applications and results of applications were given at the result part of work. Also, the performance of hardware for advanced level of image processing applications was explained.
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    Öğe
    Mobile measurement of radiofrequency electromagnetic field exposure level and statistical analysis
    (Elsevier Sci Ltd, 2016) Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, Muhammed Bahattin; Celik, Ali Recai
    In this study, radiofrequency electromagnetic field exposure levels were measured as mobile on the main streets of Diyarbakir during a week. The measurements were carried out using high precision spectrum analyzer with an isotropic antenna mounted on the top of a car. With this mobile measurement, large areas were measured in a short time and information about characteristics of electromagnetic environment was obtained quickly. Measurement results showed that measurement values were not in normal distribution and variances between independent variables were not homogeneous. According to Spearman's rho correlation coefficient, there was no strong correlation between measurement days. In terms of mean electric field values, contribution of each band to total band was arranged as UMTS DL, GSM900 DL, GSM1800 DL, TV4-5, FM, and TV3 band, respectively. It was determined that all measurement values were below the reference levels of the International Commission on Non-Ionizing Radiation Protection. (C) 2016 Elsevier Ltd. All rights reserved.