Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Conference Object Citation - WoS: 1Citation - Scopus: 1High Frequency Diffraction of Cylindrical Waves by Perfectly Conducting Successive Step Discontinuities(Institute of Electrical and Electronics Engineers Inc., 2006) Türetken, B.; Alkumru, Ali; Büyükaksoy, A.; Kuştepeli, AlpThe diffraction of high frequency cylindrical electromagnetic waves by step discontinuities is investigated rigorously by using the Fourier transform technique in conjunction with the mode matching method. The hybrid method of formulation gives rise to a scalar Wiener-Hopf equation of the third kind, the solution of which contains infinitely many constants satisfying infinite systems of linear algebraic equations.Article Citation - WoS: 32Citation - Scopus: 41Subsectional Tapered Fed Printed Lpda Antenna With a Feeding Point Patch(Institute of Electrical and Electronics Engineers Inc., 2016) Bozdağ, Göksenin; Kuştepeli, AlpIn this letter, a log-periodic dipole array (LPDA) antenna operating between 1.1 and 13.8 GHz with VSWR < 2and an average peak realized gain of 5.2 dB is presented. It is suitable for GPS (L1-L5), PCS, IMT-2000, Bluetooth, WLAN, WiMAX, UWB, and X-band applications. The antenna is designed by introducing a subsectional tapered feedline instead of standard microstrip feeding, which leads to a remarkable lower-frequency performance. The upper-frequency performance of the antenna is improved by adding a feeding point patch. The group delay is also examined for the final design, and maximum 1.5 ns deviation is observed in UWB. By using ordinary and simple dipoles with this modified feedline approach, a superior antenna performance is obtained over a very wide frequency band, and it is validated by the comparison of three fabricated antennas. Additionally, the antenna size is also reduced without using complicated and/or top-loaded dipole structures.Article Citation - WoS: 7Citation - Scopus: 10Design and Implementation of a Tem Stripline for Emc Testing(Institute of Electrical and Electronics Engineers Inc., 2014) Hilavin, Sezgin; Kuştepeli, AlpIn this paper, a stripline for radiated field immunity testing of audio/video products is designed, constructed, calibrated, and verified. Since the canonical one is only suitable for testing equipments with height less than 70 cm, there is a need of a new device which is also in compliance with EN 55020 standard for testing new large sets, like 47″ thin-film transistor liquid crystal display (TFT LCD) television sets, in the frequency range of 150 kHz-150 MHz. Increasing the height and width of testing area causes important problems in terms of field uniformity regarding the higher order modes, characteristic impedance, and reflections in addition to the room resonances and field interference sources like corners at the edges of stripline. Comprehensive numerical study is performed to overcome these problems and obtain the optimum design before the construction. Measured data show that the new stripline is in very good agreement with the specifications determined by the standards and therefore it can be used for the electromagnetic compatibility (EMC) testing.Conference Object Electromagnetic Scattering From Arbitrary Flat Plates: Analysis of the Problem by Using Method of Moments With Different Sinc Type Basis Functions(Institute of Electrical and Electronics Engineers Inc., 2011) Özbakış, Başak; Oğuzer, Taner; Kuştepeli, AlpIn this paper, three dimensional electromagnetic scattering problem is solved by using pulse-sinc type basis functions in the Method of Moments (MoM) procedure. This method is applied to the scattering problems of a plane wave illuminated flat arbitrary geometries. Pulse-sinc based MoM formulation is developed, the current densities and radar cross section of different geometries are investigated. The radar cross section (RCS) for co-polarized and cross polarized cases of the flat plate geometries are compared with both of the results obtained from the sinc-sinc based formulation and SuperNEC. The results obtained by using pulse-sinc fornulation are in very good agreement with those of the SuperNEC. © 2011 IEEE.Conference Object Citation - Scopus: 1Three-Dimensional Electromagnetic Scattering From Flat Plates by Using Sinc-Type Basis Functions in Method of Moments(Institute of Electrical and Electronics Engineers Inc., 2009) Özbakış, Başak; Oğuzer, Taner; Kuştepeli, AlpSinc functions are used in the basis and testing procedures in the conventional method of moments (MoM) formulation. But unlike conventional MoM, simple pointwise meshing is enough and no integral computation is required due to the mathematical properties of the sinc function. The simulation results of surface current densities and radar cross section for a few wavelength square flat plate are obtained by using our own codes. The results are compared with those of the rooftop basis functions. The CPU-time decreases by half of the time of the conventional method. The error that occurs from the approximated integral of the sinc function in the computation of main matrix elements is very small and decreases while the bandwidth of the sinc function increases.Conference Object Citation - WoS: 2Citation - Scopus: 2A novel square-spiral strip antenna(Institute of Electrical and Electronics Engineers Inc., 2007) Saynak, Uğur; Kuştepeli, AlpA square-spiral strip antenna is designed considering the procedure used to obtain log-periodic antennas. Simulation results of the new design are compared with those of the well known and widely used Archimedean spiral antenna in terms of the frequency dependency. The effect of dielectric substrate used to support the antennas is also investigated.Article Citation - WoS: 52Citation - Scopus: 67On the Splitting Parameter in the Ewald Method(Institute of Electrical and Electronics Engineers Inc., 2000) Kuştepeli, Alp; Martin, Anthony Q.An investigation of the Ewald method is presented. The method involves a splitting parameter that is theoretically an arbitrary number. An analysis is presented to show why the splitting parameter cannot always be treated as arbitrary in calculations and how this parameter should be chosen for all. periodic spacing of a structure.