Thesis (MscEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The aim of this thesis is to investigate the suitability of TEM (Transverse Electromagnetic) horn
antennas for use as feed structures for the Square Kilometre Array (SKA) radio telescope, in particular
with regard to the roundness of the radiation pattern. A literature study shows that existing
TEM horn designs do not yield a round radiation pattern over a wide bandwidth and that an alternative
is required. The Method of Moments (MoM) is a computational electromagnetic (CEM)
technique typically used in the analysis of TEM horn antennas. An in-house MoM solver is successfully
developed to analyse such antennas and is able to calculate the current density on the
surface of a conductor, as well as the farfield patterns of an antenna. A modification to an exponential
TEM horn antenna is proposed and simulations show the modification is successful in
yielding a round radiation pattern over a wide bandwidth. The modified exponential TEM horn has
a convex triangular arc at the end of each antenna plate and is constructed for measurement. Due to
limited construction capabilities, the measurements deviate slightly from the simulated results but
still indicate the potential of the structure to yield a round radiation pattern over a wide bandwidth. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om die geskiktheid van transverse elektromagnetiese (TEM) horing
antennas te ondersoek vir die gebruik as voerstrukture vir die Square Kilometre Array (SKA)-
radioteleskoop, veral met betrekking tot die rondheid van die stralingspatroon. ’n Literatuurstudie
toon dat bestaande TEM horing ontwerpe nie ’n ronde stralingspatroon oor ’n wye bandwydte
lewer nie, en dat ’n alternatief nodig is. Die metode van momente is ’n rekenbare elektromagnetiese
tegniek wat tipies gebruik word in die ontleding van TEM horing antennas. ’n In-huis metode van
momente ontleder is suksesvol ontwikkel om sulke antennas te analiseer en is in staat om die
stroomdigtheid op die oppervlak van ’n geleier, sowel as die vêrveld patrone van die antenna te
bereken. ’n Wysiging van ’n eksponensiële TEM horing antenna word voorgestel en simulasies
toon dat die veranderings suksesvol is om ’n ronde stralingspatroon oor ’n wye bandwydte te skep.
Die verander eksponensiële TEM horing het ’n konvekse driehoekige boog aan die einde van elke
antenna plaat en is gebou vir meting. Weens beperkte konstruksie vermoëns, toon die metings ’n
afwyking van die gesimuleerde resultate, maar dui nogsteeds die potensiaal aan van die struktuur
om ’n ronde stralingspatroon te lewer oor ’n wye bandwydte.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6833 |
| Date | 03 1900 |
| Creators | Schoeman, Karla |
| Contributors | De Villiers, D. I. L., Meyer, P., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 103 p. : ill. |
| Rights | University of Stellenbosch |
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