Thesis (MScEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: An electro-optic sensor system was developed which uses the modulated scatterer
technique [1] to measure the fine structure-amplitude and phase-of
electric fields with the minimum of perturbation. The theory for the technique
is discussed in detail, with the Lorentz Reciprocity theorem as foundation.
The system is also treated as a general two port and solved in
terms of the impedances present. This comprises self impedances and mutual
impedances.
The signals scattered by the dipole scatterer are modeled as amplitude modulated
signals and a detailed detection scheme is presented. The detection
of the signals is done by a digital correlation process. This is quite similar to
synchronous detection.
A detailed sensitivity analysis is presented that was used to determine the
quality of the system. This analysis is backed by a practical sensitivity
measurement. A few antennas and scatterers are measured in the X-band
using the system, and results are compared with theory. These systems
include a pyramidal horn, an E-plane sectoral horn and a simple waveguide.
Half plane diffraction by a metal sheet is also presented.
The practical implementation of the theory is emphasized. / AFRIKAANSE OPSOMMING: 'n Elektro-optiese meetsisteem is ontwikkel wat die gemoduleerde strooier
tegniek [11 gebruik om die fyn struktuur-amplitude en fase-van elektriese
velde te meet. Hierdie tegniek versteur die velde minimaal. 'n Volledige
ondersoek word gedoen na die teorie van die stelsel. Die basis van die metode
Ie in die Lorentz Resiprook teorie. Alhoewcl daar gekonsentreer word op
hierdie teorie, is die stelsel ook beskou as 'n tweepoort. Die wedersydse en
ei impedansies van die verskillende komponente word gebruik om die velde
op te los.
Die gestrooide seine, as gevolg van die dipool strooier, word gemodelleer met
b hulp van amplitude modulasie. Die deteksie van hierdie seine word deeglik
bespreek. In plaas van 'n analoogstelsel, word 'n digitale korrellasie proses
gebruik om die velde te meet.
Di sensitiwiteit van die stelsel word geanaliseer. Verder word metings met
di stelsel gen em om die teoretiese analise te staaf. 'n Paar X-band sisteme
word gebruik om metings te neem. Hicrdi metings word ook vergelyk met
teor ti se resultate. Stelsels wat gemeet is sluit die volgencle in: 'n piramidale
horing antenna, 'n E-vlak sektorale horing antenna, 'n X-band golfgeleier en
die diffraksi op die rand van 'n plaat.
Die praktiese implemcntering van die teorie word beklemtoon.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/51596 |
| Date | 12 1900 |
| Creators | Tait, Jan |
| Contributors | Cloete, J. H., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 102 leaves : ill. |
| Rights | Stellenbosch University |
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