SUNScholar will be down for routine maintenance from 2018-12-11 10:00 SAST.

A study on phased-array-feeds for paraboloidal reflector antennas

Ruppert, Malan Anton Xander (2017-12)

Thesis (MEng)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: This thesis presents a general study on the use and applications of paraboloidal reflectors utilizing a dense phased array feed (PAF), in the underlying context for use with a receiving Earth station antenna for satellite communication. A theoretical treatment of fundamental concepts useful in the understanding and analysis of PAF system is given, including illustrative examples regarding focal field distribution sampling with an array antenna. The important topic of embedded element patterns, which plays a vital role in including mutual coupling effects in the analysis, is discussed in some detail. A versatile linear numerical framework is created using accurate full-wave simulations and linear microwave-network equations, and combined into a convenient simulation model which can be used to perform various parameter studies on PAF systems. The model allows effects such as various front-end LNA parameters, and beamforming techniques to be investigated. The possibility of including passive array elements, or combining active elements, can also to be investigated. The simulation model is applied to an example 15-element dipole PAF, and a discussion is given on various results regarding beamsteering, optimal beamforming, and receiver noise matching. The possibility of utilizing passive elements along with mutual coupling to reduce array receiver costs is investigated. It is found that more array elements are not always better, given the fact that element contributions to overall system noise outweigh their contribution to gain. Finally, a detailed investigation is carried out on the various trade-of effects between different array configurations and system noise in the context of scanning in a single angular plane. A valuable result is obtained showing identical system SNR performance for arrays using either 9- or 45 elements.

AFRIKAANSE OPSOMMING: Hierdie tesis bied 'n algemene ondersoek oor die gebruik en aanwending van paraboloiëde weerkaatser-antennas, wat gebruik maak van brandpuntvlaksamestelling (BFS) voer antennas, in die onderliggende konteks van die gebruik daarvan in 'n ontvanger grondstasie antenna vir satellietkommunikasie. 'n Teoretiese behandeling word gegee van die fundamentele begrippe wat nuttig is in die verstaan en analise van BFS stelsels, insluitende illustratiewe voorbeelde van die toetsing van die brandpuntverspreiding op so 'n weerkaatserantenna. Die belangrike aspek van ingebedde element stralingspatrone, wat 'n belangrike rol speel om wedersydse koppeling tussen antennas te kan ondersoek, word ook bespreek. 'n Handige stel numeriese gereedskap word gegenereer met behulp van akkurate volgolf simulasies en liniêre mikrogolf netwerk vergelykings, en word gekombineer in 'n gerieflike simulasie model wat gebruik kan word om verskeie parameter studies op BFS stelsels uit te voer. Met die model kan verskillende aspekte soos 'n variasie van lae ruis versterker parameters, asook bundelvormingstegnieke ondersoek word. Die gebruik van passiewe elemente, of die geval van aktiewe elemente wat gekombineer word, kan ook ondersoek word. Die simulasiemodel word toegepas op 'n 15-element dipool BFS stelsel as voorbeeld, en verskeie resulte soos bundelstuur en optimale bundelvorming word bespreek. 'n Voorbeeld van ontvanger ruis aanpassing word ook bespreek. Die moontlike gebruik van passiewe elemente met wedersydse koppeling, met die doel om ontvanger kostes te verminder, word ondersoek. Die resultate wys dat meer elemente in 'n samestelling nie noodwendig beter is nie, aangesien sommige elemente se bydrae tot die algehele stelsel ruis meer beduidend is as hul bydrae tot antenna aanwins. 'n In-diepte ondersoek word gedoen oor die effek op stelsel ruis tussen verskillende samestelling modelle en hoeveelheid elemente, in die konteks van enkel vlak bundelstuur. 'n Waardevolle resultaat word aan die lig gebring wat identiese sein-tot-ruis verhouding aantoon vir samestellings van 9- en 45 elemente.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/102950
This item appears in the following collections: