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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Simulation of Lüneburg Lens Constructed With Glide Symmetric Periodic Structures

Forsberg, Joar, Blomqvist, Olle January 2020 (has links)
The goal of this project was to design a lens utilisinga glide symmetric periodic structure. A Lüneburg lens forantennas with a center frequency of 8 GHz has been designed.The structure was constructed using a unit cell in the shape ofan angular Bowen knot. This unit cell was then etched on themetallic surface of a parallel plate waveguide. Two symmetrycases for the unit cell were studied, the mirror symmetry andthe glide symmetry. Mirror symmetry is when the unit cell wasmirrored on the opposite metallic sheet, and glide symmetrywhen the cell was mirrored and shifted half a period. Theglide symmetric case was found to be less dispersive and moreisotropic. Further, we study the influence on the refractive indexwhen changing the geometry of the unit cell. A sufficient rangeof refractive index for realising the lens was found. These resultswere used to construct a full lens. Simulation of the complete lensshows the desired point to planar wave behavior of a Lüneburglens. In conclusion, the angular Bowen knot with glide symmetryhas the potential to construct a functioning Lüneburg lens. / Målet för detta projekt var att konstrueraen lins med glidsymmetriska periodiska strukturer. En Lüneburg-lins för antenner med en centerfrekvens på 8 GHz har de-signats. Strukturen byggdes med en enhetscell i formen avett sankthanskors etsat på en metallisk plattkondensator fylldmed ett dielektriskt substrat. Två symmetrifall betraktades,spegelsymmetri, då enhetscellen speglades på motstående me-tallskikt, och glidsymmetri där den även var förskjuten en halvperiod. Glidsymmetrin fanns ha mindre spridning och störreisotropi. Därtill undersöktes förändringarna i brytningsindex dåenhetscellens geometri förändrades. En tillräcklig räckvidd avbrytningsindex kunde uppnås. Dessa resultat användes för attkonstruera en fullständig lins. Simulering av den kompletta linsenvisade det önskade punkt till planvågbeteendet hos en Lüneburglins. Slutsatsen är att enhetsceller i formen av ett sankthanskorsmed glidsymmetri har potentialen att konstruera fungerandeLüneburg-linser. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

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