Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Radar Cross Section (RCS) is an important parameter in radar engineering.
Often, electrically large structures are of interest in RCS analysis due to the
high operating frequencies of radar systems. Simulation of these problems can
be more e cient than measurement due to the cost associated with measurement.
The Method of Moments/Physical Optics (MoM/PO) hybrid method
combines the advantages of the MoM and PO, making it suited to solving
electrically large problems that may contain some small complex detail. The
requirement for high meshing resolution when analysing some electromagnetic
problems, however, signi cantly increases memory requirements. As a result,
the hybrid MoM/PO becomes computationally expensive for electrically large
problems. In this work, a linear phase term is introduced into the RWG basis
function formulation of the MoM/PO hybrid. The addition of the linear
phase term allows the use of large triangular mesh elements in the PO region,
resulting in the analysis of electrically large problems. The bene t of this
formulation is that it allows a reduction in computational cost whilst maintaining
the accuracy of the hybrid MoM/PO. This improved hybrid is tested
on various planar test cases and results show that it attains the same level of
accuracy as the original MoM/PO hybrid. / AFRIKAANSE OPSOMMING: Radardeursnit is 'n belangrike parameter in radaringenieurswese. As gevolg
van die hoë frekwensies wat deur baie radarstelsels gebruik word, is elektriesgroot
probleme dikwels van belang in die berekening van die radardeursnit van
teikens. Die modellering en berekening van die radardeursnit van teikens kan
meer kostedoeltre end as metings wees, as gevolg van die beduidende koste
van radardeursnitmetings. Die hibriede Moment-Metode/Fisiese-Optika tegniek
kombineer die voordele van die twee tegnieke, wat dit geskik maak vir
elektries-groot probleme met klein, komplekse detail. Indien die gewone benadering
egter gevolg word om 'n hoë resolusie faset-model te gebruik, bly
dit berekeningsintensief met groot rekenaar geheuevereistes vir elektries-groot
probleme. In hierdie studie word 'n lineêre fase term ingesluit in die formulering
van die Rao-Wilton-Glisson (RWG) basisfunksies vorm van die hibriede
Moment-Metode/Fisiese-Optika tegniek. Die toevoeging van die lineêre fase
term maak dit moontlik om groot driehoekfasette in die Fisiese-Optika gebied
te gebruik, wat beteken dat elektries-groot probleme makliker opgelos kan
word. Die voordeel van hierdie nuwe formulering is dat die berekeningslas en
-tyd verminder word terwyl die akkuraatheid van die oorspronklike hibriede
Moment-Metode/Fisiese-Optika tegniek behou word. Hierdie verbeterde hibriede
tegniek word getoets aan die hand van verskeie platvlak toetsgevalle en
die resultate dui daarop dat die akkuraatheid vergelykbaar is met die van die
oorspronklike hibriede Moment-Metode/Fisiese-Optika tegniek.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20060 |
| Date | 03 1900 |
| Creators | Nazo, Syanda |
| Contributors | Davidson, D. B., Smith, J. C., 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 | 87 p. : ill. |
| Rights | Stellenbosch University |
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