Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551433
Title: Modelling the microwave transmission of metal arrays using modal matching
Author: Taylor, Melita Clare
Awarding Body: University of Exeter
Current Institution: University of Exeter
Date of Award: 2012
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Abstract:
This work explores the interaction of electromagnetic radiation with periodic metal-dielectric composite materials. In particular, the majority of the studies explore the role of evanescent diffraction in the regime where the wavelength of the incident radiation is of the order of the period of the array just below the onset of diffraction. The underlying aim of the thesis is to build on the current knowledge and gain deeper understanding into the causal mechanism of the electromagnetic response of these periodic materials. Developments in metamaterial research have led to a resurgance of interest in the use of periodic metallic surface to control the transmission of electromagnetic radiation. The response of these surfaces can be `tuned' to provide the required response simply by altering the geometric parameters of the material. Numerical modelling techniques are often used to predict the response of such structures. However, the aim of this work is to gain a deeper understanding of the reasons for the response and therefore an analytical modal matching method has been used. The modal matching method provides the opportunity to extract greater understanding of the resonant phenomena by linking them to specific mathematical terms in the analytical formulation. The modal matching technique is initially used to study the response from a single layer bigrating comprising a square array of square holes in a PEC sheet and its complementary system of a square array of square PEC patches. The importance of evanescent diffraction in both resonant phenomena and tunneling responses is discussed and it is shown that complete transmission (reflection) is supported by these structures even for very high (low) metal occupancy. This technique is extended and adapted to describe a variety of structures in chapters 5 and 6, exploring how resonant excitation of surface waves via evanescent diffraction leads to highly interesting electromagnetic responses. In chapter 7, alternating multilayer stacks of two different subwavelength meshes provide an observable one-dimensional topological mode in a physical system for particular mesh configurations.
Supervisor: Sambles, J. Roy Sponsor: BAE Systems Ltd
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.551433  DOI: Not available
Keywords: Physics ; modal matching ; arrays ; microwave
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