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Conference Object Citation - Scopus: 2Design and Fabrication of Ka Band Circular Horn Antenna;(2012) Danaci,S.; Gürtekin,E.; Özyurt,E.; Kara,A.In this paper, design and fabrication of a circular horn antenna is presented. The antenna is designed for experimental use at Ka band. The design process includes feeding structure for coaxial line and geometrical parameters of the antenna. The bandwidth of the antenna is measured as 2.25GHz, (S 11 ≤-10dB) which satisfies the requirements of targeted experimental study. A reference monopole is also designed for the measurements of antenna parameters. Antenna radiation pattern is measured with the reference monopole antenna using a VNA (S12) instead of typical signal generator/spectrum analyzer pair. Accuracy of antenna parameters along with the errors made in fabrication process is also discussed in the paper. © 2012 IEEE.Conference Object Citation - Scopus: 20Design and Development of a Remote and Virtual Environment for Experimental Training in Electrical and Electronics Engineering(2010) Kara,A.; Aydin,E.; Ozbek,M.E.; Cagiltay,N.European Remote Radio Laboratory (ERRL) has been developed by the support of European Commission. It intends to provide remote access to high cost devices remotely, and perform experiments in radio frequency (RF), communications and microwave domains of Electrical ad Electronics Engineering. The system has been operational for two years, and been integrated into curriculum of some courses. In this work, the hardware and software structures of the system are presented. Then, experimental content and the motivations in the design of the system are discussed. ©2010 IEEE.Article Citation - Scopus: 11Modelling of Shadowing Loss Due To Huge Non-Polygonal Structures in Urban Radio Propagation(Electromagnetics Academy, 2008) Kara,A.; Yazgan,E.Ray tracing algorithms rely on two dimensional or three dimensional database. They use ray optical techniques referred to as the uniform theory of diffraction (UTD) using building database given as polygons. Building geometries can also be modelled as having non-planar geometries, and this would be important in modeling of shadowing loss due to curved structures in urban radio propagation. To demonstrate modelling of buildings as non-polygonal geometries, a particular building composition involving 3D cruved geometries is chosen, and shadowing loss for this building composition is studied via UTD ray tracing. Building structure considered in this study involves main canonical shapes of non-planar geometries including cone, cylinder and sphere. Single and multiple interaction of surface diffractions, effect of creeping waves are taken into consideration in the analysis. © 2008, Electromagnetics Academy.Conference Object Citation - Scopus: 4Distance Laboratory Applications Errl: a Study on Radio Communication in Electronic Field(2008) Aydin,C.Ç.; Türkmen,G.; Özyurt,E.; Aydm,E.U.; Çaǧiltay,N.E.; Özbek,M.E.; Kara,A.In the last decade, the effect of internet usage in education is gradually increased. When we look from academic perspective, the new technologies provided alternatives for students learning. As distance education becomes important everyday, the indispensable elements of teaching and education, laboratories must be reachable via remote connection. Consequently, the education that is going to be given to the students will be more flexible with respect to place and time constraints and students can reach laboratory facilities at any time and anywhere not only in lectures and practical hours. In this study, European Remote Radio Laboratory (ERRL) which is a distance remote Radio Frequency (RF) laboratory designed for electrical-electronics students, is described generally. The software architecture, infrastructure and experiment that can be done with a remote connection have been described.Conference Object Citation - Scopus: 1Characterization of satellite transponder impairments based on simulations with test data(Institute of Electrical and Electronics Engineers Inc., 2015) Ulubey,O.; Gulgonul,S.; Kara,A.A satellite transponder simulator based on actual test data of TURKSAT 3A satellite has been developed to analyze degradation in multicarrier scenarios. Communication impairment sources through a transponder are explained in conjunction with a methodology defined to characterize total degradation resulting from them. Several transponder utilization scenarios are studied with respect to total degradation and optimum operation conditions are demonstrated. © 2015 IEEE.Conference Object Citation - Scopus: 2New Wavelet-Based Features for the Recognition of Jittered and Stagger Pri Modulation Types;(Institute of Electrical and Electronics Engineers Inc., 2015) Gencol,K.; Kara,A.; At,N.In dense electronic warfare environments, numerous emitters can be active simultaneously and an interleaved stream of pulses in natural time of arrival order is received by the Electronic Support Measures (ESM) receiver. It is the task of the ESM system to de-interleave this mixed pulse sequence and thus to identify the surrounding threatening emitters. In this processing, pulse repetition interval (PRI) modulation recognition has a significant role due to the fact that it can reveal the hidden patterns inside pulse repetition intervals and thus help identify the emission source and its functional purpose. In this paper, we propose new wavelet-based features for the recognition of jittered and stagger PRI modulation types. The recognition of these types are heavily based on histogram features. Experimental results show that the proposed feature set have very high recognition rates and outperform histogram based methods. © 2015 IEEE.Conference Object Citation - Scopus: 25Blockage/Shadowing and Polarization Measurements at 2.45ghz for Interference Evaluation Between Bluetooth and Ieee 802.11 Wlan(2001) Kara,A.; Bertoni,H.L.We present measurement results at 2.45 GHz to evaluate blockage shadowing and fading effects due to furniture and people next to terminals for short range indoor communication systems. The followings are the results: people crossing the link near to a terminal can cause fading up to 20dB which is more than furniture blockage measured of about 5-13dB depending on objects over the links, polarization coupling was also measured by using dual polarized antenna at receiving end, and coupling is higher for obstructed links, which suggests polarization diversity.Conference Object Citation - Scopus: 2A Modular Fmcw Radar Rf Front End Design: Simulation and Implementation;(IEEE Computer Society, 2014) Daǧdeviren,B.; Kapusuz,K.Y.; Kara,A.In this work, simulations and preliminary measurement results of an S-band FMCW radar is presented. A commercial simulation tool (AWR-VSS) has been used at system level design stage of the radar. The simulation tool provides all functions regarding with transmitter, target and receiving blocks, and it finally feeds echo signals to the digital processing block implemented in MATLAB. The target range and velocity have been derived for simple target scenario in MATLAB. Then, a modular RF front end of the radar has been designed using commercial of the shelf (COTS) components. The radar system has been proved to be working in indoor environment using measurement equipment. Moreover, design of horn antennas for transmitting and reception blocks have been demonstrated. Real time signal processing functions will be developed at the next stage. © 2014 IEEE.Conference Object Citation - Scopus: 11Design of Low-Cost Modular Rf Front End for Rf Fingerprinting of Bluetooth Signals(Institute of Electrical and Electronics Engineers Inc., 2017) Uzundurukan,E.; Ali,A.M.; Kara,A.For RF fingerprinting of wireless devices, data acquisition has a critical role. Because of this, highly sophisticated devices are used for data capturing or acquisition. In this paper, design of a RF receiver front end with modular components is presented. This design contains filtering and down conversion processing of Bluetooth signals for cellular phones. Moreover, AWR VSS and MATLAB have been used for simulating the down converter circuit. With this simulation, effects of components that used in the design on recorded signal have been observed. In this work in progress paper, only high SNR conditions are considered. © 2017 IEEE.Conference Object Citation - Scopus: 2Measurement of Local Environmental Effects in Uwb Channels(2006) Vural,M.D.; Yildiz,M.; Kara,A.[No abstract available]
