Thesis (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The implementation and verification of a recently proposed Huy gens' principle in hollow
lossless waveguide is described. The extended Huygens' principle is applicable
to the scattering effect of arbitrary obstacles in waveguide and allows the coupling
of a volume Finite Element discretization with a quasi Method of Moments surface
element approach. A review of the technique is given and expressions for the two port
scattering parameters are derived. The implementation is restricted to posts in rectangular
waveguide, although the technique may also be applied to general scattering
problems in waveguide. Finite Elements for the volume of the obstacle are selected
and a basis set is proposed. The elemental finite element matrices are derived for a low
and higher order basis set, while the validity of the derivations is established by considering
a simple waveguide example. A coupled set of matrix equations is constructed
that can be solved for the unknown surface electric and magnetic fields and the volume
magnetic fields. A set of test examples is chosen to verify the implementation. The
convergence behaviour is examined for two test cases. The dissertation concludes with
an evaluation of the technique and recommendations for future work. / AFRIKAANSE OPSOMMING: Die implementasie en verifiëring van 'n onlangs voorgestelde Huygens beginsel in
leë golfleier word beskryf. Die uitgebreide beginsel van Huygens is van toepassing
op die strooiingseffek van arbitrêre voorwerpe in verlieslose golfleier en beskryf die
koppeling tussen 'n volume eindige element diskretisasie met 'n oppervlakelement
kwasi-moment metode. 'n Oorsig oor die tegniek word gegee en uitdrukkings vir die
tweepoort strooiingsparameters word afgelei. Die implementering word beperk tot
penne in reghoekige golfleier, alhoewel die tegniek op algemene golfleier strooiingsprobleme
van toepassing is. Eindige elemente word gekies vir die volume van die
voorwerp en 'n basisfunksie versameling afgelei van bestaande basisfunksies. Lae
en hoë orde element matrikse word afgelei en die geldigheid van die afleidings word
nagegaan deur 'n eenvoudige golfleier probleem op te los. 'n Gekoppelde stel matriksvergelykings
word opgestel in terme van die onbekende oppervlak elektriese en
magnetiese velde. 'n Aantal toetsvoorbeelde word gekies om die implementasie te
verifieer. Konvergensiegedrag word ondersoek vir twee toetsgevalle. Die proefskrif
sluit af met 'n evaluasie van die tegniek en aanbevelings vir verdere werk.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53725 |
| Date | 04 1900 |
| Creators | Geschke, R. H. (Riana Helena) |
| Contributors | Davidson, D. B., Meyer, P., Ferrari, R. L., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 70 p. : ill. |
| Rights | Stellenbosch University |
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