Yazar "Abbasov, Teymuraz" seçeneğine göre listele

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    Development of a High Gain, Dual-Band and Two-Layer Miniaturized Microstrip Antenna for 5.8 GHz ISM and 10 GHz X-Band Applications
    (Applied Computational Electromagnetics Soc, 2019) Atas, Isa; Abbasov, Teymuraz; Kurt, Muhammed B.
    In this study, it is explained how to increase the gain of a two-layer stacked miniaturized microstrip patch antenna (MPA) operating at 5.8 GHz and 10 GHz step by step by combining several different methods used in the literature for performance improvement of MPAs. A commonly used FR4 substrate material was preferred to design and produce the antenna. For electromagnetic modeling of the prototype structure, numerical analysis, and optimization, ANSYS HFSS was used. The performance of the proposed antenna was evaluated in terms of return loss (RL), surface current distribution, radiation patterns and gain/directivity. To confirm the study, the simulation results were compared with the measurements taken over the antenna prototype and good agreement has been achieved. The peak gain values of the proposed antenna at 5.8 GHz and 10 GHz are obtained as 4.11 dBi and 7.15 dBi, respectively.
  • Küçük Resim
    Öğe
    Diyarbakır İl Merkezi’nde UMTS bandının mobil ölçümü ve istatistiksel analizi
    (Dicle Üniversitesi Mühendislik Fakültesi, 2016) Cansız, Mustafa; Abbasov, Teymuraz; Çelik, Ali Recai; Kurt, Muhammed Bahaddin
    Mobil haberleşme sistemlerinde çok hızlı teknolojik gelişmeler gözlemlenmektedir. Global System for Mobile Communications (GSM) ve Universal Mobile Telecommunications System (UMTS) gibi ikinci ve üçüncü nesil mobil haberleşme sistemleri zamanla daha yaygın bir şekilde kullanılırken Long Term Evolution (LTE) gibi dördüncü nesil mobil haberleşme sistemi ülkemizde yeni hizmet vermeye başlamıştır. Bu da, dış ortamdaki elektromanyetik alan maruziyet seviyesinin artmasına neden olmaktadır. Bu çalışmada, UMTS bandının Diyarbakır İl Merkezi’nde yer alan ana caddelerde yaymış olduğu elektrik alan şiddeti değerleri bir hafta boyunca mobil olarak ölçülmüştür. Daha sonra, elde edilen ölçüm sonuçları istatistiksel olarak analiz edilmiştir. Ayrıca, UMTS bandına ait bir günlük mobil ölçüm verileri iki ve üç boyutlu olarak harita üzerinde gösterilmiştir. Mobil ölçümlerde, spektrum analizör cihazı, üç eksenli elektrik alan ölçüm anteni, bağlantı kabloları ve elde edilen mobil ölçüm verilerini kaydetmek için dizüstü bilgisayarı kullanılmıştır. Bu ölçümlerde en yüksek anlık elektrik alan şiddeti değeri 6.0900 V/m ve en düşük anlık elektrik alan şiddeti değeri ise 0.0724 V/m olarak ölçülmüştür. Bununla birlikte, UMTS bandında ölçülen ortalama elektrik alan şiddeti değerleri dikkate alındığında ortalaması en yüksek olan gün Çarşamba günü ve değeri ise yaklaşık 0.6281 V/m olarak ölçülmüştür. Buna karşın, ortalaması en düşük gün ise Pazartesi günü ve değeri yaklaşık 0.5936 V/m olarak ölçülmüştür. Standart sapma ve varyans değişiminin en fazla olduğu gün Çarşamba günü olmuştur. Ayrıca, Spearman’s rho korelasyon katsayılarına göre UMTS bandının ölçüm günleri arasında yüksek korelasyon yoktur. Birbirine en çok benzeyen günlerin Pazartesi ile Çarşamba günleri olduğu ve Spearman’s rho korelasyon katsayısının 0.643 olduğu belirlenmiştir. Buna karşın, en az benzeyen günlerin ise Perşembe ve Cuma günleri olduğu ve Spearman’s rho korelasyon katsayısının 0.276 olduğu tespit edilmiştir
  • Küçük Resim
    Öğe
    Doğrusal ve düzlemsel mikroşerit dizi antenlerin tasarımı ve kazanç yönünden karşılaştırılması
    (Dicle Üniversitesi Mühendislik Fakültesi, 2018) Ataş, İsa; Abbasov, Teymuraz; Kurt, Muhammed Bahaddin
    Bu çalışmada, S frekans band aralığındaki çevresel algılama uygulamalarında kullanılacak iki farklı mikroşerit dizi anten tasarımı sunulmuştur. Yapılan bu çalışma doğrusal ve düzlemsel mikroşerit dizi antenlerin yüksek kazanç yönünden benzetim sonuçlarının karşılaştırılmasını içermektedir. Dizi anten tasarımı aşamasında yüksek kazanç ile birlikte yönlü ışıma yapan anten modelleri amaçlanmıştır. 1x4 ve 2x2 dizi anten modelleri, kolay elde edilebilen, maliyeti ucuz olan dielektrik sabiti 4.4 ve kalınlığı yaklaşık 1.6 mm olan FR4 yalıtkan malzeme ile hazırlanmıştır. Dizi antenler, üç boyutlu tam dalga elektromanyetik yapı analizi ANSOFT HFSS programı kullanılarak tasarlanmıştır. Tasarım aşamasında dizi antenlerin iletim hattı kayıpları T-junction ve Wilkinson güç bölücüsü teknikleri kullanılarak optimize edilmeye çalışılmış ve empedans uyumu gerçekleştirilmiştir. Ayrıca iletim hattındaki istenilmeyen yansımaları minimum seviyeye çekmek ve kapasitif yüklenmeyi azaltmak için dönemeçlerdeki gereksiz alanlar kaldırılmıştır. Tek elemanlı antenin ürettiği kazanç 2.64 dB ve yönelticilik 6.69 dB iken, çeyrek dalga dönüşüm besleme ile tasarlanan 1x4 ve 2x2 dizi antenlerde sırasıyla 9.10 dB ve 7.10 dB kazanç ve 12.29 dB ve 11.18 dB yönelticilik değerleri gözlemlenmiştir. Aradaki kazanç kaybı, kullanılan dielektrik malzemenin kayıplı bir yapıya sahip olmasından dolayıdır. Önerilen 1x4 ve 2x2 dizi antenlerin çıkış parametrelerinden yansıma kaybı (RL), duran dalga oranı (VSWR), giriş empedansı, kazanç ve ışıma örüntü diyagramları karşılaştırmalı olarak verilmiştir.
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    GAIN ENHANCEMENT AND MINIATURIZATION OF DUAL-BAND COMPACT PATCH ANTENNA
    (2020) Ataş, İsa; Abbasov, Teymuraz; Kurt, Muhammed Bahaddin
    In this study, how to increase the dual-band Patch Antenna (PA) gain for the performance improvement of PAs is explained step by step. In addition, a novel method was added for further miniaturization and gain enhancement of the PA. Low cost FR4 substrate was preferred for the design and production of this model. The performance of the proposed antenna was evaluated in terms of Return Loss (RL), surface current distribution, gain and radiation efficiency. For this purpose, HFSS which is a commercial software and that solves electromagnetic structures by finite element method was used in modeling and design steps. The prototype of the produced antenna was measured with a vector network analyzer and the output characteristics were evaluated. The measurement and simulation results of this antenna were found to be consistent and comparable. The peak gain values of the proposed antenna at 5.8 GHz and 10 GHz were obtained as 2.88 dBi and 7.24 dBi, respectively.
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    High Gain Microstrip Antenna Design for 2.4GHz WLAN Application
    (Ieee, 2015) Atas, Isa; Kurt, M. Bahaddin; Abbasov, Teymuraz
    IEEE 802.11x standard widely used in wireless local area network systems is called Wi-Fi as well. In this study high gain Microstrip Antenna (MA) design is presented for 2.4 GHz WLAN application. Simulations were made on parameters such as the geometry and size of antennas, type of dielectric material, the thickness of substrate for most appropriate designing of antenna. For simulations, HFSS software which is a full wave and finite element based simulator was used. Total maximum gain of the designed antenna were obtained as 9.06 dB.
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    High Gain Rectangular Microstrip Array Antenna Design at 2.6GHz
    (Ieee, 2016) Atas, Isa; Kurt, M. Bahaddin; Abbasov, Teymuraz
    In this study, especially the ability to be used in WiMAX applications, high-gain microstrip line feed 2 x I patch array antenna design work was done. Antenna simulation of this antenna design made using HFSS 3D gain and directivity characteristics were simulated. Since antenna impedance is greater than line impedance, impedance matching has been made with inset - fed microstrip line and thequarter-wavetransformer. The results show that the proposed antenna parameters are sufficient for WiMAX applications.
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    Mapping of radio frequency electromagnetic field exposure levels in outdoor environment and comparing with reference levels for general public health
    (Springernature, 2018) Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, M. Bahattin; Celik, A. Recai
    In this study, radio frequency electromagnetic field exposure levels were measured on the main streets in the city center of Diyarbakir, Turkey. Measured electric field levels were plotted on satellite imagery of Diyarbakir and were compared with exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposure measurements were performed in dense urban, urban and suburban areas each day for 7 consecutive days. The measurement system consisted of high precision and portable spectrum analyzer, three-axis electric field antenna, connection cable and a laptop which was used to record the measurement samples as a data logger. The highest exposure levels were detected for two places, which are called Diclekent and Batikent. It was observed that the highest instantaneous electric field strength value for Batikent was 7.18 V/m and for Diclekent was 5.81 V/m. It was statistically determined that the main contributor band to the total exposure levels was Universal Mobile Telecommunications System band. Finally, it was concluded that all measured exposure levels were lower than the reference levels recommended by ICNIRP for general public health.
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    Measurement and Comparison of Signal Levels of GSM900, GSM1800 and UMTS Bands
    (İsmail SARITAŞ, 2016) Cansız, Mustafa; Abbasov, Teymuraz; Kurt, M.Bahattin; Celık, A.Recai
     Signal levels of GSM900, GSM1800 and UMTS bands were measured as mobile on the main streets in the city center of Diyarbakır at the same time and route during a week. The measurements were performed by using high precision and portable spectrum analyzer with an isotropic electric field antenna and a laptop. The high precision spectrum analyzer is a device that measures the high frequency electromagnetic fields. The isotropic electric field antenna allows a three axis measurements. The laptop was used to record and analyze the measurement samples. Electric field strengths were measured as signal levels in this study. Some statistical parameters such as standard deviation and variance were calculated with 95% confidence interval for measurement samples. The highest signal levels were measured as 3.8580 V/m for GSM 900 band, 2.9440 V/m for GSM1800 band and 6.0900 V/m for UMTS band during a week. Similarly, mean electric field strength values as average signal levels were calculated as 0.4985 V/m for GSM 900 band, 0.2350 V/m for GSM1800 band and 0.6281 V/m for UMTS band. According to the mean electric field strength values, the average signal levels of three bands were ranked as UMTS, GSM900 and GSM1800 from the largest to the smallest, respectively. The highest variation in standard deviation and variance was observed on Wednesday for GSM900 and UMTS bands and Thursday for GSM1800 band.
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    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.