Effective Medium Theory for Anisotropic Metamaterials

Handle URI:
http://hdl.handle.net/10754/626171
Title:
Effective Medium Theory for Anisotropic Metamaterials
Authors:
Zhang, Xiujuan ( 0000-0002-2375-3449 )
Abstract:
This dissertation includes the study of effective medium theories (EMTs) and their applications in describing wave propagation in anisotropic metamaterials, which can guide the design of metamaterials. An EMT based on field averaging is proposed to describe a peculiar anisotropic dispersion relation that is linear along the symmetry line but quadratic in the perpendicular direction. This dispersion relation is associated with the topological transition of the iso-frequency contours (IFCs), suggesting interesting wave propagation behaviors from beam shaping to beam splitting. In the framework of coherent potential approximation, an analytical EMT is further developed, with the ability to build a direct connection between the microscopic structure and the macroscopic material properties, which overcomes the requirement of prior knowledge of the field distributions. The derived EMT is valid beyond the long-wavelength limit. Using the EMT, an anisotropic zero-index metamaterial is designed. Moreover, the derived EMT imposes a condition that no scattered wave is generated in the ambient medium, which suggests the input signal cannot detect any object that might exist, making it invisible. Such correspondence between the EMT and the invisibilityinspires us to explore the wave cloaking in the same framework of coherent potential approximation. To further broaden the application realm of EMT, an EMT using the parameter retrieval method is studied in the regimes where the previously-developed EMTs are no longer accurate. Based on this study, in conjunction with the EMT mentioned above, a general scheme to realize coherent perfect absorption (CPA) in anisotropic metamaterials is proposed. As an exciting area in metamaterials, the field of metasurfaces has drawn great attention recently. As an easily attainable device, a grating may be the simplest version of metasurfaces. Here, an analytical EMT for gratings made of cylinders is developed by using the multiple scattering theory (MST) method and the lattice sum. Validation of the theory is verified by the agreement between the EMT predictions and the numerical calculations. It is found the EMT is capable of accurately predicting the wave transport behaviors, even for frequencies where the Mie resonances happen.
Advisors:
Wu, Ying ( 0000-0002-7919-1107 )
Committee Member:
Ketcheson, David I. ( 0000-0002-1212-126X ) ; Bagci, Hakan ( 0000-0003-3867-5786 ) ; Chang, Yia-Chung
KAUST Department:
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Program:
Applied Mathematics and Computational Science
Issue Date:
12-Nov-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorWu, Yingen
dc.contributor.authorZhang, Xiujuanen
dc.date.accessioned2017-11-20T08:42:19Z-
dc.date.available2017-11-20T08:42:19Z-
dc.date.issued2017-11-12-
dc.identifier.urihttp://hdl.handle.net/10754/626171-
dc.description.abstractThis dissertation includes the study of effective medium theories (EMTs) and their applications in describing wave propagation in anisotropic metamaterials, which can guide the design of metamaterials. An EMT based on field averaging is proposed to describe a peculiar anisotropic dispersion relation that is linear along the symmetry line but quadratic in the perpendicular direction. This dispersion relation is associated with the topological transition of the iso-frequency contours (IFCs), suggesting interesting wave propagation behaviors from beam shaping to beam splitting. In the framework of coherent potential approximation, an analytical EMT is further developed, with the ability to build a direct connection between the microscopic structure and the macroscopic material properties, which overcomes the requirement of prior knowledge of the field distributions. The derived EMT is valid beyond the long-wavelength limit. Using the EMT, an anisotropic zero-index metamaterial is designed. Moreover, the derived EMT imposes a condition that no scattered wave is generated in the ambient medium, which suggests the input signal cannot detect any object that might exist, making it invisible. Such correspondence between the EMT and the invisibilityinspires us to explore the wave cloaking in the same framework of coherent potential approximation. To further broaden the application realm of EMT, an EMT using the parameter retrieval method is studied in the regimes where the previously-developed EMTs are no longer accurate. Based on this study, in conjunction with the EMT mentioned above, a general scheme to realize coherent perfect absorption (CPA) in anisotropic metamaterials is proposed. As an exciting area in metamaterials, the field of metasurfaces has drawn great attention recently. As an easily attainable device, a grating may be the simplest version of metasurfaces. Here, an analytical EMT for gratings made of cylinders is developed by using the multiple scattering theory (MST) method and the lattice sum. Validation of the theory is verified by the agreement between the EMT predictions and the numerical calculations. It is found the EMT is capable of accurately predicting the wave transport behaviors, even for frequencies where the Mie resonances happen.en
dc.language.isoenen
dc.subjectEffective Medium Theoryen
dc.subjectAnisotropic Metamaterialsen
dc.subjectwave cloakingen
dc.subjectwave absorptionen
dc.subjectgrating structureen
dc.titleEffective Medium Theory for Anisotropic Metamaterialsen
dc.typeDissertationen
dc.contributor.departmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberKetcheson, David I.en
dc.contributor.committeememberBagci, Hakanen
dc.contributor.committeememberChang, Yia-Chungen
thesis.degree.disciplineApplied Mathematics and Computational Scienceen
thesis.degree.nameDoctor of Philosophyen
dc.person.id123091en
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