Analysis of large disjoint antenna arrays by localised solutions

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dc.contributor.advisorBotha, Matthysen_ZA
dc.contributor.authorChose, Matthewsen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.en_ZA
dc.date.accessioned2023-03-03T07:56:27Zen_ZA
dc.date.accessioned2023-05-18T07:14:10Zen_ZA
dc.date.available2023-03-03T07:56:27Zen_ZA
dc.date.available2023-05-18T07:14:10Zen_ZA
dc.date.issued2023-03en_ZA
dc.descriptionThesis (PhD)--Stellenbosch University, 2023.en_ZA
dc.description.abstractENGLISH ABSTRACT: The method of moments (MoM) is well suited to the full-wave electromagnetic analysis of antenna arrays. This is especially true for perfect electrically conducting (PEC) antennas, when an electric field integral equation (EFIE) formulation with Rao-Wilton-Glisson (RWG) basis functions is the typical approach. This yields fully populated matrices with the solution cost growing rapidly with array size N, as O(N3) and O(N2) for the runtime and storage respectively, when a standard direct solver is employed. This work is concerned with the efficient an d re liable EF IE RWG MoM an alysis of large antenna arrays consisting of identical disjoint PEC elements. Examples of such arrays are encountered within the international Square Kilometre Array (SKA) project, which motivates this work. The new formulations proposed are based on a MoM domain decomposition technique known as the domain Green’s function method (DGFM), which is a perturbation technique developed for analysing large disjoint antenna arrays. It was originally formulated in the context of printed substrate antennas, but has since been applied more broadly. In its existing form, the DGFM is limited to fairly sparse arrays where mutual coupling effects are less pronounced. Three DGFM-based extensions are proposed, in order for the method to be applicable to dense and very large antenna arrays. The first i s t o i ntroduce l arger l ocal solution domains in combination with an iterative scheme, to enable solutions to a pre-specified accuracy. The second is a physics-based row expansion direct-coupling technique, which is a necessary variation on the standard DGFM approach to far couplings, in order to maintain efficiency wh en de aling wi th mu ltiple si ngle-element ex citations fo r embedded element pattern calculations. Thirdly, a hybrid, single-level adaptive cross approximation (ACA) matrix compression scheme is proposed, which is tailored to the acceleration of the DGFM and is applicable to both new formulations. Results for antenna arrays relevant to the SKA low-frequency band show efficient and reliable performance.en_ZA
dc.description.abstractAFRIKAANS OPSOMMING: Die moment metode (MoM) is goed geaard vir vol-golf elektromagnetiese analise van antenna samestellings. Dis veral die geval vir perfekte geleier (PG) antennas, in welke geval ’n elektriese veld integraalvergelyking (EVIV) formulering met Rao-Wilton-Glisson (RWG) basis funksies, die tipiese benadering is. Dit lei tot vol matrikse, met oplossingskoste wat vinnig groei met betrekking tot samestellingsgrootte N, as O(N3) en O(N2) vir die looptyd en stoorspasie, onderskeidelik, wanneer ’n standaard direkte oplosser gebruik word. Hierdie werk is gemoeid met die doeltreffende en b etroubare EVIV RWG MoM analise van groot antenna samestellings, wat bestaan uit identiese onverbinde PG elemente. Voorbeelde van sulke samestellings kom voor met die internasionale “Square Kilometre Array (SKA)” projek, wat dien as motivering vir hierdie werk. Die voorgestelde nuwe formulerings is gebaseer op ’n MoM domein-dekomposisie tegniek wat bekendstaan as die domein Green funksie metode (DGFM), wat ’n perturbasie tegniek is, wat ontwikkel is vir die analise van groot onverbinde antenna samestellings. Dit is oorspronklik geformuleer in die gedrukte substraat antenna konteks, maar is latervantyd meer uiteenlopend aangewend. Die DGFM in bestaande vorm, is beperk tot betreklike yl samestellings, waar die invloed van wedersydse koppeling beperk is. Drie DGFM-gebaseerde uitbreidings word voorgestel, om sodoende die metode toepaslik te maak vir digte en baie groot amestellings. Die eerste is om vergrote plaaslike gebiede in te voer, asook uitbreiding na ’n iteratiewe skema, om sodoende plossingsakkuraatheid te kan beheer. Die tweede is ’n fisiese, r y-uitbreiding gebaseerde, direkte-koppelingstegniek, wat ’n vereiste aanpassing tot die standaard DGFM se vêrkoppelingsvoorstelling is, om sodoende doeltreffendheid te handhaaf vir analise van enkelelement aandrywings vir ongewingsgewyse element patroon berekeninge. Derdens word ’n hibriede, enkel-vlak aanpassingsvaardige kruis-benadering (AKB) matriks saampersingskema voorgestel, wat aangepas is tot die versnelling van die DGFM en toepaslik is tot albei nuwe formulerings. Antenna samestelling resultate wat relevant is tot die SKA laefrekwensie band, toon doeltreffende en betroubare werkverrigting.af_ZA
dc.description.versionDoctorateen_ZA
dc.format.extentxvi, 94 pages : illustrationsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/127287
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshMoments method (Statistics)en_ZA
dc.subject.lcshAntenna arraysen_ZA
dc.subject.lcshElectromagnetic wavesen_ZA
dc.titleAnalysis of large disjoint antenna arrays by localised solutionsen_ZA
dc.typeThesisen_ZA
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Doctoral Degrees (Electrical and Electronic Engineering)