It is well known that quad-ridged horn antennas in general have impedance and radiation
characteristics that are significantly worse than that of their double-ridged counterparts.
Normally a voltage standing wave ratio (VSWR) of 3 over the operational bandwidth is
used for the design specification of quad-ridged horn antennas. The bandwidth of operation
is severely restricted due to the excitation of higher order modes in the co-axial to
waveguide transition of the antenna. The higher order modes cause a break-up in the
radiation pattern of the antenna and large dips in the boresight gain.
The performance of the quad-ridged horn antenna with pyramidal sidewalls is improved by
separating the antenna into the transition and flared horn sections, and optimizing these
sections individually. It is shown that a transition section with a pyramidal cavity and
steps, and a flared horn section with an exponential profile with a circular segment for the
ridges deliver the best performance. These configurations for the transition and flared horn
sections are combined in the complete antenna. The optimized antenna has a 12.5:1
operational bandwidth with improved performance in terms of the VSWR, the coupling
between the ports and the boresight gain. A prototype of this antenna is manufactured.
Good agreement between the measured and simulated performance is achieved. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Electrical, Electronic and Computer Engineering / unrestricted
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:up/oai:repository.up.ac.za:2263/33343 |
| Date | January 2013 |
| Creators | Van der Merwe, Pieter Hugo |
| Contributors | Odendaal, J. W., Joubert, Johan |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | © 2013 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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