Browsing by Author "Sevgi, Levent"
Now showing items 1-20 of 174
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Analytical & numerical calculations of S-parameters in multilayer DPS-DNG junctions
Çimen, Sibel; Çakır, Gonca; Sevgi, Levent (IEEE, 2009-01)Metamaterials (MTM) have recently attracted much attention in electromagnetic engineering. Initial studies have focused on understanding their electromagnetic properties and responses, but applications have also begun to ... -
Analytical and numerical investigations of ring resonators
Akleman, Funda; Sevgi, Levent (IEEE, 2007)Rectangular vs. cylindrical finite-difference time-domain (FDTD) electromagnetic modeling is discussed, and characteristic tests and comparisons are presented depending on the analytical and numerical analysis of ring type ... -
The antenna as a transducer: simple circuit and electromagnetic models
Sevgi, Levent (IEEE, 2007-12)Antennas are key elements in electrical engineering. They are the first and most essential parts of a communication/radar system, and basic instruments for electromagnetic compatibility (EMC) tests and measurements. A good ... -
Antenna calibration for EMC tests and measurements
Sevgi, Levent; Çakır, Soydan; Çakır, Gonca (IEEE, 2008-06)An antenna is calibrated in an open-field test site (OFTS) and/or an anechoic chamber, which facilities themselves need calibration. The procedures for calibrated test sites (CALTS) are given in the CISPR and ANSI/IEEE ... -
Backscattering from a soft-hard strip: primary edge waves approximations
Hacıvelioğlu, Feray; Sevgi, Levent; Ufimtsev, Pyotr Yakovlevich (IEEE, 2013)High-frequency approximation is constructed for backscattering from a strip with one face soft and the other face hard (i.e., with Dirichlet and Neumann boundary conditions, respectively). This approximation is based on ... -
Biostatistics and epidemiology: hypothetical tests on cell phone users
Sevgi, Levent (IEEE, 2010-02)This paper aims to discuss, in its simplest form, the complexity of the interaction of electromagnetic waves with human tissue in terms of epidemiological research and biostatistics. It also reviews the application of ... -
A broadband array of Archimedean spiral antennas for wireless applications
Sevgi, Levent; Çakır, Gonca (John Wiley & Sons, 2006-01-01)A low-cost, small-size, broadband antenna array of Archimedean spiral elements is designed with beam-steering and interference-nulling capabilities for mobile platforms (for example, laptop computers). Its adaptive ... -
Calibration of three - dimensional parabolic - equation propagation models with the rectangular waveguide problem
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2011-12)The Split-Step-, Finite-Element-, and Finite-Difference-Method-based three-dimensional (3D) wave-propagation prediction simulators using the parabolic equation (PE) are calibrated against reference data derived from ... -
A canonical test problem for computational electromagnetics (CEM): propagation in a paralel - plate waveguide
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2012-08)This paper aims to provide a tutorial on computational electromagnetics (CEM), and simple MATLAB codes for sophisticated investigation of analytical and well-known numerical models. The problem of propagation inside a ... -
Challenging electromagnetic problems and numerical simulation approaches
Sevgi, Levent (Springer, 2004-02-20)Applications in science and technology rely increasingly on electromagnetic (EM) field computations in either man-made or natural complex structures or environments. Also, majority of these applications are based on digital ... -
Comment on "fringe waves in an impedance half-plane"
Hacıvelioğlu, Feray; Sevgi, Levent; Ufimtsev, Pyotr Yakovlevich (Electromagnetics Academy, 2014)This paper (i.e., [1]) extends PTD to an impedance half-plane problem. -
Comments on "propagation modeling over irregular terrain by the improved two-way parabolic equation method"
Özgün, Özlem; Apaydın, Gökhan; Kuzuoğlu, Mustafa; Sevgi, Levent (IEEE, 2014-07)The above paper [1] is about the two-way split-step parabolic equation method (2W-SSPE) over irregular terrain, and claims that they have developed the “improved” version of the 2W-SSPE approach that has been proposed and ... -
Comparative study of analytical and numerical techniques in modeling electromagnetic scattering from single and double knife - edge in 2d ground wave propagation problems
Özgün, Özlem; Sevgi, Levent (ACES, 2012-05)This paper presents a comparative study of some analytical and numerical techniques in the solution of a classical problem of electromagnetic scattering from single and double knife edge above ground. The results of the ... -
Comparison of rectangular and cylindrical FDTD representations on a ring resonator problem
Akleman, Funda; Sevgi, Levent (TÜBİTAK, 2008)The aim of this paper is to discuss rectangular and cylindrical representations of finite-difference time-domain (FDTD) method over characteristic tests and comparisons. A ring resonator is chosen as a canonical structure ... -
A critical review on electromagnetic precursors and earthquake prediction
Sevgi, Levent (TÜBİTAK, 2007)Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public ... -
DEMSEE 2007: deregulated electricity market issues in South-Eastern Europe
Sevgi, Levent; Doğuş Üniversitesi, Mühendislik Fakültesi, Elektronik ve Haberleşme Mühendisliği Bölümü; TR143819; Belirlenecek (Doğuş Üniversitesi, 2007-09)It is true that Electricity is a pillar for our present Civilization and Culture. One should also recognize that Electricity is the finest useable form of Energy and therefore the most precious. Deregulation of Electricity ... -
A design of a microstrip electromagnetic dual-band bandgap (DB-EBG) structure
Çakır, Gonca; Sevgi, Levent (John Wiley & Sons, 2006-07)The design, simulation, and experimentation steps of a novel low-cost, small-size microstrip electromagnetic dual-band bandgap (DB-EBG) structure is presented. The numerical simulations are performed via an in-house-prepared ... -
Design of a novel microstrip electromagnetic bandgap (EBG) structure
Sevgi, Levent; Çakır, Gonca (John Wiley & Sons, 2005-08-20)This paper presents the design, simulation, and experimentation of a novel low-cost small-size high-performance microstrip (MS) electromagnetic bandgap (EBG) structure for MIMIC applications. The simulations and measurements ... -
Design of a novel microstrip electromagnetic bandgap (EBG) structure
Sevgi, Levent; Çakır, Gonca (John Wiley & Sons, 2005-08-20)This paper presents the design, simulation, and experimentation of a novel low-cost small-size high-performance microstrip (MS) electromagnetic bandgap (EBG) structure for MIMIC applications. The simulations and measurements ... -
Design, simulation and tests of a low-cost microstrip patch antenna arrays for the wireless communication
Çakır, Gonca; Sevgi, Levent (TÜBİTAK, 2005)Typical low-cost, low-weight microstrip base station antenna arrays with beam-scanning capabilities are taken into account. In downtowns of large cities like New York, Chicago, and in historical cities like Istanbul, where ...
