Browsing by Author "Zoral, Emine Yesim"

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Citation - WoS: 15
Citation - Scopus: 18
Hierarchical Reconstruction and Structural Waveform Analysis for Target Classification
(Institute of Electrical and Electronics Engineers Inc., 2016) Alper Mustafa Selver; Mehmet Mert Taygur; Mustafa Seçmen; Emine Yeşim Zoral; Zoral, Emine Yesim; Selver, Mustafa Alper; Taygur, Mehmet Mert; Secmen, Mustafa
Classification of objects from scattered electromagnetic waves is a difficult problem as it heavily depends on aspect angle. To minimize this dependency distinguishable features can be used. In this paper we propose a target identification method in the resonance scattering region using a novel structural feature set based on the scattered signal waveform. To obtain robustness at low signal-to-noise ratio (SNR) a multiscale approximation is used for distortion correction prior to the feature extraction. This is achieved by an overlapping grid hierarchical radial basis function (HRBFOG) network topology which is demonstrated to outperform existing HRBF techniques. The results obtained from the simulations and the measurements performed for various targets show high accuracy for classification with the proposed feature set robustness through the use of HRBF at low SNR and efficient computation in real time. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Metamaterial Characteristics of Dielectric Resonator Arrays in Rectangular Waveguide and Free space
(IEEE, 2015) Gizem Kalender; Mustafa Secmen; Emine Yesim Zoral; Zoral, Emine Yesim; Secmen, Mustafa; Kalender, Gizem
The study demonstrates the metamaterial characteristics of the arrays containing dielectric resonators by evaluating the permittivity and permeability coefficients of the array structures in rectangular waveguide and free space. For this purpose the array with two closely spaced dielectric resonators is setup and placed both in a rectangular waveguide and free space one by one. The scattering parameters in both structures are extracted with full-wave simulations (CST Microwave Studio) and supported with measurement results. Then the effective relative permittivity and permeability values are obtained with the deembedding technique and retrieval method. According to the results the structures show double negative (DNG) characteristics at some frequencies. Therefore the array with dielectric resonators is shown to have metamaterial characteristics. Besides the DNG frequencies of both (waveguide and free space) structures are found to be consistent to each other. This means that the metamaterial behaviour of the dielectric resonator array is highly insensitive to the wave excitation where TE10 and TEM modes are excited in rectangular waveguide and free space respectively.