It is known that the 1-18 GHz Double Ridge Guide Horn (DRGH) antenna is highly
sensitive to tolerances in manufacturing. Since a typical DRGH antenna is constructed
from a number of individual parts, tolerances in the machining, even when numerically
controlled, and errors in the assembly can easily lead to gaps between subsections.
Performance deviations, most notably resonances in the boresight gain and VSWR was
observed in a number of manufactured 1-18 GHz DRGH antennas. The exact cause of the
performance deviations had to be determined in order to identify which sections of the
antenna need to be redesigned in such a way that the effects of the manufacturing and
assembling tolerances on the performance of typical mass produced DRGH antennas are
reduced or eliminated. It was hypothesised that gaps most notable in the waveguide
launcher section and especially the coaxial feeding section is the cause of the sharp
resonance effects. This hypothesis was confirmed during the study. A highly accurate
Method of Moments (MoM) numerical model of the 1-18 GHz DRGH antenna was
developed, gaps were then implemented in between various parts of the model and the
results observed. Based on these results a new improved 1-18 GHz DRGH antenna was
designed with reduced sensitivity to manufacturing tolerances and improved performance. / Dit is alombekend dat die 1-18 GHz Dubbel Rif Golfleier Horing (DRGH) antenna baie
sensitief is vir vervaardigings toleransies. 'n Tipiese DRGH antenna bestaan uit verskeie
individuele onderdele. Toleransies in vervaardiging, selfs al word die proses numeries
beheer, kan dus lei tot spasies tussen verskillende dele. Die waarneming van verswakte
werkverrigting, meer spesifiek resonansies in die wins en Spannings Staande Golf
Verhouding (SSGV) by 'n aantal vervaardigde 1-18 GHz DRGH antennes het gelei tot
verdere studie. Om die 1-18 GHz ontwerp minder sensitief te maak ten opsigte van
toleransies, moes die presiese oorsaak van die verswakte werkverrigting bepaal word. Aan
die begin van die studie was die vermoede dat spasies in veral die golfleierlanseerder en
meer spesifiek die koaksiale voer seksie, die oorsaak is van die resonansies. Die hipotese is
in die daaropvolgende ondersoek bevestig. 'n Hoogs akkurate Metode van Momente
(MvM) numeriese model is vir die 1-18 GHz DRGH antenna ontwikkel. Spasies is tussen
verskeie parte van die model ge-inkorporeer en die resultate is ondersoek. 'n Nuwe
verbeterde 1-18 GHz DRGH antenna op die ondersoek gebaseer, is ontwikkel. Die antenna
het verminderde sensitiwiteit ten opsigte van vervaardigings toleransies sowel as
verbeterde werkverrigting. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / Unrestricted
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:up/oai:repository.up.ac.za:2263/30834 |
| Date | 20 May 2011 |
| Creators | Jacobs, Bennie |
| Contributors | Odendaal, J.W. (Johann Wilhelm), bennie.jacobs@za.saabgroup.com, Joubert, Johan |
| Publisher | University of Pretoria |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Dissertation |
| Rights | © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
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