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dc.contributor.supervisor Mojabi, Puyan (Electrical and Computer Engineering) en_US
dc.contributor.author Brown, Trevor
dc.date.accessioned 2021-01-12T16:59:40Z
dc.date.available 2021-01-12T16:59:40Z
dc.date.copyright 2020-12-22
dc.date.issued 2020-12 en_US
dc.date.submitted 2020-12-22T17:22:35Z en_US
dc.identifier.citation Trevor Brown, Chaitanya Narendra, Yousef Vahabzadeh, Christophe Caloz, and Puyan Mojabi, "On the use of electromagnetic inversion for metasurface design", IEEE Transactions on Antennas and Propagation, vol. 68. no. 3, pp. 1812-1824, 2020. en_US
dc.identifier.citation Trevor Brown, Yousef Vahabzadeh, Christophe Caloz, and Puyan Mojabi, "Electromagnetic inversion with local power conservation for metasurface design", IEEE Antennas and Wireless Propagation Letters, vol. 19, no. 8, pp. 1291-1295, 2020. en_US
dc.identifier.citation Trevor Brown, and Puyan Mojabi, "Cascaded metasurface design using electromagnetic inversion with gradient-based optimization", IEEE Transactions on Antennas and Propagation, submitted July 2020, under review. en_US
dc.identifier.uri http://hdl.handle.net/1993/35207
dc.description.abstract This thesis presents the theory and development of a framework for the design of electromagnetic metasurfaces. These metasurfaces can be used to systematically transform an incident electromagnetic field into a different transmitted field, providing new levels of control not typically possible with conventional materials. Although a metasurface is made up of subwavelength scattering elements, it can be macroscopically represented as a homogenized model using effective surface susceptibilities. These tensorial surface susceptibilities define the relationship between the tangential electric and magnetic fields on either side of the metasurface through a set of generalized boundary conditions known as the generalized sheet transition conditions. In this work we concern ourselves with macroscopic metasurface design, the goal of which is to find an appropriate set of surface susceptibilities to support a desired field transformation. Up until now, macroscopic design methods have been mostly limited to ideal cases in which analytical expressions of the input and output fields are fully known. While this limitation is acceptable for simpler applications such as refraction, reflection, or polarization manipulation of plane waves, more general transformations, such as producing a desired far-field radiation pattern, pose a challenge. To address the above limitation, we propose framing macroscopic metasurface design as an electromagnetic inverse source problem. We show that the equivalent currents produced by solving an appropriately constructed inverse source problem are directly related to the tangential transmitted fields required to compute the surface susceptibility parameters that characterize the metasurface. The design method is developed for several different types of field specifications, namely complex (amplitude and phase) fields, phaseless (amplitude-only) power patterns, and far-field performance criteria (e.g., main beam direction, beamwidth, null locations, etc.). We then show that local power conservation can be enforced during the inversion process, allowing for the design of metasurfaces that only require passive, lossless, and reciprocal elements. Lastly, we extend the framework to the design of cascaded metasurfaces. This introduction of a second metasurface removes the need to have equal input and output power distributions, thereby increasing the variety of supported field transformations. en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Electromagnetic metasurfaces en_US
dc.subject Inverse problems en_US
dc.subject Optimization en_US
dc.subject Antenna pattern synthesis en_US
dc.subject Inverse source problems en_US
dc.title Metasurface design using electromagnetic inversion en_US
dc.type info:eu-repo/semantics/doctoralThesis
dc.type doctoral thesis en_US
dc.degree.discipline Electrical and Computer Engineering en_US
dc.contributor.examiningcommittee Okhmatovski, Vladimir (Electrical and Computer Engineering) Asadzadeh, Masoud (Civil Engineering) Hum, Sean (University of Toronto) en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note February 2021 en_US


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