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Conference Object Citation - Scopus: 2Miniaturized 2.4 Ghz Antenna Design for Uav Communication Link;(Institute of Electrical and Electronics Engineers Inc., 2020) Yilmaz,V.S.; Kara,A.; Aydin,E.In many communications applications, unlike conventional antennas, lightweight, flexible, small antennas that can adapt to mechanical and industrial constraints are required. In this study, the results of antenna design operating at 2.4 GHz are presented for use in Unmanned Aerial Vehicle (UAV) tele command links. In the parametric and optimization studies carried out on the antenna, it is aimed to increase the gain while keeping the size as small as possible. The requirements of the industry, such as light, aesthetics, miniature and high gain aspects of the antenna were targeted in the design process. Finally, an antenna of 55.2x88 mm size and 7dB gain was achieved using commercial electromagnetic design tools. The designed antenna become satisfying industrial requirements with these features. © 2020 IEEE.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: 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: 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: 4Design of a Scenario-Based Synthetic Mixed Pulse Generator;(2013) Gençol,K.; Kara,A.; At,N.Electronic Support Measures (ESM) plays an important role in modern Electronic Warfare (EW) systems. The main purpose of an ESM system is to intercept as many emissions as it can, and then to deinterleave mixed streams of pulses that are interleaved in natural time of arrival order, and thus to identify surrounding emissions. In real life, such systems may encounter with a continuous stream of pulses accompanied by many imperfections, and it should work on real-time basis. In order to handle such circumstances and to develop better deinterleaving algorithms, a simulation tool is needed. In this study, design of a scenario-based mixed pulse generator (simulator) is presented. © 2013 IEEE.Conference Object A study for development of propagation model based on ray tracing for coverage prediction in terrestrial broadcasting systems;(2009) Tabakcioǧlu,M.B.; Özmen,A.; Kara,A.In this work, improvements on propagation prediction models based on ray tracing in coverage estimation for digital broadcasting systems are presented. For this purpose, firstly, propagation models based on Geometrical Theory of Diffraction (GTD) are discussed, and then an improved model is proposed for prediction of propagation path loss or electric field strength at the receiver. The proposed model incorporates first order expansion of classical GTD in field computation and convex hull for ray tracing. Simulation results are presented for comparison of various models in terms of computation time and accuracy. ©2009 IEEE.Conference Object Specific Emitter Identification using video signals;(2012) Erdem,C.; Kara,A.Specific Emitter Identification(SEI) methods are used in intercept systems for differentiating of same type of emitters in the environment. Most of the SEI implementations are designed for post processing (off line) by operators. This paper presents preliminary results on real time (on line)implementation of a SEI method on signals after the IF stage, i.e, video signals after the detector section. Initially, only the envelope of the pulses are considered in SEI processing. Pulse width and energy are two main parameters used in SEI algorithm developed. On the other hand, one of the main problems in operational environments is multipath distotion on received pulses. Most of the SEI algorithms require higher SNR figures for providing reliable results. Moreover, creating and running of a library is another issue. This paper presents various approaches in both processing of multipath distorted pulses and wavelet based library creating methods on real-time SEI implementation for an intercept receiver. © 2012 IEEE.Conference Object Citation - Scopus: 7Spectrum Analysis of Parabolic Range Gate Pull-Off (rgpo) Signals;(Institute of Electrical and Electronics Engineers Inc., 2015) Ozturk,M.T.; Dalveren,Y.; Kara,A.Digital Radio Frequency Memory (DRFM) is a method that is used to capture radar threat signals, and retransmit them by changing their parameters in order to deceive or manipulate radar threats. Range gate pull-off (RGPO) technique is widely used in DRFM methods. RGPO can be either linear or parabolic RGPO according to the applied pull-off function. In this study, firstly, analytical derivations for temporal and spectral analysis of discrete form of linear and parabolic RGPO signals are presented. Then, various scenarios dependent on the parameters of pull-off function are created. Finally, simulation results regarding the scenarios are presented. © 2015 IEEE.Conference Object Citation - Scopus: 2A New Approach To Threat Tracking on Esm Systems by Using Kalman Filters;(2009) Çelebi,M.B.; Kara, Ali; Kara,A.; Akar,B.; Tümay,A.; Dinçer,K.; Kara, Ali; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics EngineeringKalman filtering (KF) is a form of recursive estimator, which has been widely applied to different applications. This paper discusses a new approach, based on a discrete event process, for tracking of threats (emitters). Pulses of a particular threat from received mixed (raw) pulse sequences of multiple threats corrupted by timing jitter and measurement noises are aimed to be tracked. Required parameters to initiate KF are taken from identification algorithm which begins before KF algorithm. Hereby, KF runs on mixed pulse train. The algorithm based on KF is adaptive to both the noise and missing pulses together with large time gaps between pulses of the threat. The algorithm is robust and efficient due to the fact that it includes various distinctive parameters of the threat such as frequency (TF), pulse width (DG), angle of arrival (GA) and scan patterns (TO). ©2009 IEEE.
