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Identifier |
000415081 |
Title |
Metasurfaces for control of electromagnetic waves |
Alternative Title |
Μετα-επιφάνειες για τον έλεγχο ηλεκτρομαγνητικών κυμάτων |
Author
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Χατζημπαλόγλου , Κωνσταντίνος Όθων
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Thesis advisor
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Καφεσάκη, Μαρία
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Reviewer
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Τζωρτζάκης, Στέλιος
Παπάζογλου, Δημήτριος
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Abstract |
Μetamaterials are a man-made form of matter, manufactured with the purpose of achieving non-conventional electromagnetic (EM) properties. The manipulation of electromagnetic radiation achieved with the metametarials can be used in a multiple of applications, from telecommunications to imaging and detection. Control of EM wave propagation in metamaterials is caused, in most cases, by elements (meta-atoms) with resonance at wavelengths much larger than their dimensions. The goal of my Thesis focuses on meta-surfaces (i.e. metamaterials with thickness much smaller than wavelength) suitable for application on steering or focusing of light/electromagnetic waves. These reflect-arrays consist of identical metallic antennas which introduce abrupt phase changes on the reflected wave. These changes are of geometric origin and by rotating the antennas properly (in respect to the polarization plane of the incident wave), they can reach values from 0 to 2π. The aim is to investigate and identify the optimal shape/geometry of the antennas to achieve steering or focusing of the reflected wave.
In the current thesis we discuss first the basic characteristics of meta-surfaces and geometrical phase, called Pancharatnam-Berry phase. The numerical results of the work were made with the use of the software Microwave Studio from Computer Simulation Technology (CST). In our numerical study we mainly focus on reflection amplitude of the cross-polarization state and the respected phase response for the selected shapes of seven antennas. For each structure, under circularly polarized light, the amplitude, phase and direction of the cross-polarized reflected wave are investigated. In addition, by arranging the antennas in a suitable manner to achieve focusing from the meta-surface, we demonstrate focusing of the reflected electromagnetic wave, which resembles a Bessel-like beam.
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Language |
English |
Subject |
Metamaterials |
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Μεταϋλικά |
Issue date |
2018-03-23 |
Collection
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School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/1/1/b/metadata-dlib-1522158558-504847-773.tkl
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Views |
273 |