Browsing by Author "Apaydın, Gökhan"
Now showing items 1-20 of 24
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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 ... -
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 ... -
Diffraction modeling by a soft-hard strip using finite-difference time-domain method
Uslu, Mehmet Alper; Apaydın, Gökhan; Sevgi, Levent (IEEE, 2017)Diffraction by a strip with one face soft and the other face hard boundary condition is modeled numerically using finite-difference time-domain method, and the results are compared to the method of moments, which was ... -
Double tip diffraction modeling: finite difference time domain vs. method of moments
Uslu, Mehmet Alper; Apaydın, Gökhan; Sevgi, Levent (IEEE, 2014-12)Discontinuities such as tips and edges cause diffracted electromagnetic waves interact with objects. Two-dimensional (2D) wedge with non-penetrable boundaries is a canonical structure which has long been investigated ... -
EMC/EMI problems and diffraction modeling: Finite difference time domain vs. method of moments
Uslu, Mehmet Alper; Apaydın, Gökhan; Sevgi, Levent (IEEE, 2014-12)Edge and/or tip diffraction has long been investigated. Early attempts were analytical and called High Frequency Asymptotics (HFA). With the use of computers, numerical approaches have also appeared. In this study, two ... -
An FDTD - based waveguide filter simulator: calibration against analytical models
Apaydın, Gökhan; Sevgi, Levent (Wiley, 2013-07)A three-dimensional (3D) finite-difference time-domain (FDTD) simulator is developed for the investigation of network (S-) parameters of rectangular cross-section waveguide filters. The simulator is calibrated against ... -
FEM-based surface wave multimixed-path propagator and path loss predictions
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2009)A finite element method (FEM)-based surface wave propagation prediction simulator is developed. The simulator is tested and calibrated against analytical ray-mode models that also take into account the Millington recovery ... -
Groundwave propagation at short ranges and accurate source modeling
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2013-06)Radiowave propagation models have long been used in long-range communication and/or radar systems. Different models use different sources. Observed and calculated results are therefore usually normalized, either against ... -
MATLAB-based FEM - parabolic-equation tool for path-loss calculations along multi-mixed-terrain paths
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2014-06)A novel Finite-Element Method - Parabolic-Equation (FEMPE) based MATLAB tool is developed. This calculates the electromagnetic field strength and path loss for one-way, forward propagation over multi-mixed irregular terrain ... -
Method of moments (MoM) modeling for resonating structures: propagation inside a parallel plate waveguide
Apaydın, Gökhan; Sevgi, Levent (ACES, 2012)Method of Moments (MoM) modeling inside resonating structures is discussed and a novel approach called Multi-MoM (Mi-MoM) is proposed. Propagation inside a two-dimensional (2D) non-penetrable parallel plate waveguide is ... -
A novel split - step parabolic - equation package for surface - wave propagation prediction along multiple mixed irregular - terrain paths
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2010-08)A novel MATLAB (TM)-based split-step parabolic-equation (SSPE) propagation package is introduced for the prediction of electromagnetic surface-wave attenuation along multiple mixed irregular and lossy paths. The impedance ... -
A novel two - way finite - element parabolic equation groundwave propagation tool: tests with canonical structures and calibration
Apaydın, Gökhan; Özgün, Özlem; Kuzuoğlu, Mustafa; Sevgi, Levent (IEEE, 2011-08)A novel two-way finite-element parabolic equation (PE) (2W-FEMPE) propagation model which handles both forward and backward scattering effects of the groundwave propagation above the Earth's surface over irregular terrain ... -
Numerical investigations of and path loss predictions for surface wave propagation over sea paths including hilly island transitions
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2010-04)Surface wave propagation along multi-mixed-paths with irregular terrain over spherical Earth in two-dimension (2D) is discussed. For the first time in the literature, sea-land-sea (island) transition problem including ... -
PETOOL: MATLAB - based one-way and two - way split - step parabolic equation tool for radiowave propagation over variable terrain
Özgün, Özlem; Apaydın, Gökhan; Kuzuoğlu, Mustafa; Sevgi, Levent (Elsevier, 2011-12)A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation ... -
Propagation modeling and path loss prediction tools for high frequency surface wave radars
Apaydın, Gökhan; Sevgi, Levent (TÜBİTAK, 2010)Propagation modeling and simulation approaches for the use of High Frequency Surface Wave Radar (HFSWR) are discussed. HFSWR uses vertically polarized surface waves along multi-mixed paths in the lower HF band (3 MHz - 15 ... -
The split - step - fourier and finite - element - based parabolic - equation propagation - prediction tools: canonical tests, systematic comparisons and calibration
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2010-06)Powerful propagation-prediction tools, based on the split-step Fourier-transform and the Finite-Element-Method (FEM) solutions of the parabolic equation (PE) are discussed. The parabolic equation represents one-way ... -
Two - way propagation modeling in waveguides with three - dimensional finite - element and split - step fourier - based pe approaches
Apaydın, Gökhan; Sevgi, Levent (IEEE, 2011)Two-way, three-dimensional finite element and split-step Fourier-based parabolic equation (PE) wave propagation prediction algorithms are developed, and MATLAB-based simulators are introduced. The simulators are calibrated ... -
Two-way Fourier split step algorithm over variable terrain with narrow and wide angle propagators
Özgün, Özlem; Apaydın, Gökhan; Kuzuoğlu, Mustafa; Sevgi, Levent (IEEE, 2010-07)Helmholtz's wave equation can be approximated by means of two differential equations, corresponding to forward and backward propagating waves each of which is in parabolic wave equation (PWE) form. The standard PWE is very ... -
Two-way split-step Fourier and finite element based parabolic equation propagation tools: Comparisons and calibration
Apaydın, Gökhan; Özgün, Özlem; Kuzuoğlu, Mustafa; Sevgi, Levent (IEEE, 2010-07)Parabolic equation (PE) has long been widely used in groundwave propagation modeling [1] because of its high capability in modeling atmospheric refraction and irregular terrain effects. It yields accurate electromagnetic ...
