Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The aggressive space mapping algorithm is used in this project for the optimisation of electromagnetic
structures. This technique combines the use of fast, less accurate models with more
time-consuming, high precision models in the optimisation of a design.
MATLAB’s technical computing environment possesses powerful tools for optimisation as well
as the graphical representation and mathematical post-processing of data. A software interface,
which uses Visual Basic for Applications, is created between MATLAB and the electromagnetic
solvers, CST Microwave Studio and μWave Wizard, that are used for the fine and coarse model
calculations. The interface enables the direct interchange of data, which allows MATLAB to control
the optimisation for the automation of the design process.
The optimisation of a microwave coaxial resonator with input coupling is used to demonstrate the
design environment. An accurate equivalent circuit model is available to describe the problem.
The space mapping optimisation of this structure works well, with a significant improvement in
the efficiency of the optimisation when compared to standard optimisation techniques.
Multimode horn antennas are of interest for use as feeds in radio-astronomy telescope systems.
The design of a stepped circular horn antenna in the space mapping design environment is presented.
The horn’s radiation pattern is optimised for low cross-polarisation. This structure is much
more complex to model than the resonator example. The generalised scattering matrix representation
is used in the coarse model description. The far-fields are calculated from the aperture fields
by means of the Fast Fourier Transform. Various tests confirm that the optimisation is steered
in the right direction as long as the coarse model response follows the trend of the fine model
response over the optimisation space.
The presented design environment is a powerful tool for the automation of the design of electromagnetic
structures. / AFRIKAANSE OPSOMMING: Die aggressiewe ruimte-afbeelding algoritme word in hierdie projek gebruik vir die optimering van
elektromagnetiese strukture. Hierdie tegniek kombineer die gebruik van vinnige, minder akkurate
modelle tesame met tydrowende hoë presisie modelle tydens die optimering van ’n ontwerp.
MATLAB se tegniese verwerkingsomgewing beskik oor kragtige gereedskap vir optimering sowel
as die grafiese voorstelling en wiskundige verwerking van data. ’n Sagteware koppelvlak, wat
Visual Basic for Applications benut, word geskep tussen MATLAB en die elektromagnetiese
oplossers, CST Microwave Studio en μWave Wizard, wat vir die fyn en growwe model berekeninge
gebruik word. Hierdie koppelvlak maak die direkte uitruiling van data moontlik, wat MATLAB in
staat stel om die optimering te beheer ten einde die ontwerpsproses te outomatiseer.
Die optimering van ’n mikrogolf koaksiale resoneerder met intree koppeling word gebruik om
die ontwerpsomgewing te demonstreer. ’n Akkurate ekwivalente stroombaanmodel is beskikbaar
om die probleem mee te beskryf. Die ruimte-afbeelding optimering van hierdie struktuur werk
goed en toon ’n aansienlike verbetering in die doeltreffendheid van die optimering wanneer dit
met standaard optimeringstegnieke vergelyk word.
Multimodus horingantennes is van belang in radio-astronomie, waar dit as voere vir teleskope gebruik
word. Die ontwerp van ’n trapvormige, sirkelvormige horingantenne in die ruimte-afbeelding
ontwerpsomgewing word aangebied. Die stralingspatroon van die horing word optimeer vir lae
kruispolarisasie. Hierdie struktuur is heelwat meer ingewikkeld om te modelleer as die resoneerder
voorbeeld. Die veralgemeende strooimatriks voorstelling word gebruik in die growwe model
beskrywing. Die ver-velde word bereken vanaf die velde in die bek van die antenne, deur gebruik
te maak van die Vinnige Fourier Transform. Verskeie toetse bevestig dat die optimering in die
regte rigting gestuur word, solank as wat die growwe model se gedrag dié van die fyn model oor
die optimeringsgebied navolg.
Die ontwerpsomgewing wat hier aangebied word, is ’n kragtige stuk gereedskap vir die outomatisering
van die ontwerp van elektromagnetiese strukture.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/5144 |
| Date | 12 1900 |
| Creators | Van der Walt, Madele |
| Contributors | 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 | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 111 p. : ill. |
| Rights | University of Stellenbosch |
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