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Transient analysis of closed- and open-region electromagnetic problems using higher order finite element method and method of moments in the time domain

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dc.contributor.authorŠekeljić, Nada J., author
dc.contributor.authorNotaroš, Branislav M., advisor
dc.contributor.authorMueller, Jennifer, committee member
dc.contributor.authorReising, Steven C., committee member
dc.contributor.authorChandrasekar, V., committee member
dc.contributor.authorIlić, Milan M., committee member
dc.date.accessioned2015-08-27T03:57:19Z
dc.date.available2016-06-03T06:30:24Z
dc.date.issued2015
dc.description.abstractThe principal objective of this dissertation is to develop computational electromagnetic (CEM) methodology and tools for modeling of closed (waveguide and cavity based) and open (radiation and scattering) electromagnetic structures in the time domain (TD), employing two CEM approaches. The first method is a novel higher order and large-domain Galerkin finite element method (FEM) for transient analysis of multiport microwave waveguide devices with arbitrary metallic and dielectric discontinuities. It is based on geometrical modeling using Lagrange interpolation generalized hexahedral elements, spatial field expansion in terms of hierarchical curl-conforming polynomial vector basis functions, time-stepping with an implicit unconditionally stable finite difference scheme using the Newmark-beta method, and mesh truncation introducing the waveguide port boundary condition. The second method is a novel spatially large-domain and temporally entire-domain method of moments (MoM) proposed for surface integral equation (SIE) modeling of 3-D conducting scatterers in the TD. The method uses higher order curved Lagrange interpolation generalized quadrilateral geometrical elements, higher order spatial current expansions based on hierarchical divergence-conforming polynomial vector basis functions, and temporal current modeling by means of orthogonal weighted associated Laguerre basis functions. It implements full temporal and spatial Galerkin testing and marching-on-in-degree (MOD) scheme for an iterative solution of the final system of spatially and temporally discretized MoM-TD equations. Numerical examples of waveguides and scatterers, modeled using flat and curved large elements in conjunction with field/current expansions of orders from 2 to 9, demonstrate excellent accuracy, efficiency, convergence, and versatility of the proposed methodologies. The results obtained by higher order TD-FEM and TD-MoM are in an excellent agreement with indirect solutions obtained from FEM and MoM analyses in the frequency domain (FD) in conjunction with discrete Fourier transform and its inverse, as well as with measurements and alternative full-wave numerical solutions in both TD and FD.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierSekeljic_colostate_0053A_12958.pdf
dc.identifier.urihttp://hdl.handle.net/10217/166992
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
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dc.subjectfinite element method
dc.subjectnumerical techniques
dc.subjecttransient response
dc.subjectmethod of moments
dc.subjectelectromagnetic analysis
dc.subjectscattering
dc.titleTransient analysis of closed- and open-region electromagnetic problems using higher order finite element method and method of moments in the time domain
dc.typeText
dcterms.embargo.expires2016-06-03
dcterms.embargo.terms2016-06-03
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineElectrical and Computer Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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