Thesis (MSCIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Bi-polar Si transistors optimized for pulse conditions is still the most popular choice as
amplification element in the final stages of solid-state radar amplifiers in L and S band. With the
radar market being small, the design data for these devices is normally fairly limited and it is up to
the designers to thoroughly characterize them for their designs. This is normally done through loadpull
experiments. Professional automated load-pull equipment is very expensive especially at the
higher power levels. In spite of being automated and under computer control, load-pull exercises
still is very time consuming and as such expensive. For small companies that only occasionally need
to design such amplifiers it is not economically viable to acquire such equipment and different
strategies have to be found to stay competitive.
This report investigates such a strategy and its implementation.
A procedure to quickly and accurately characterize such devices was developed and two amplifiers
were designed and build with this procedure and compared to their traditional counterparts for
verification. The results were very promising and with a bit more work, the technique can likely be
used to characterize these devices for design work outside of the parameters designated by the
manufacturers. / AFRIKAANSE OPSOMMING: Bipolere Silikon transistors wat vir werking onder gepulsde toestande geoptimiseer is, is nog steeds
die mees gewilde keuse as versterkingselement in die finale stadiums van vastetoestand radar
versterkers in die L en S bande. Met die radar mark wat geredelik klein is, is die ontwerp inligting vir
hierdie elemente gewoonlik redelik karig en is dit die taak van die ontwerpers om die elemente te
karakteriseer vir hulle ontwerp doeleindes. Dit word normaalweg gedoen deur lastrek eksperimente.
Geoutomatiseerde lastrek toerusting is baie duur, veral as dit onder hoë drywingstoestande moet
werk. Al is die toerusting geoutomatiseer en onder rekenaar beheer, is lastrek oefeninge nog steeds
baie tydrowend en daarom dan ook baie duur. Vir klein maatskappye wat net nou en dan nodig het
om sulke versterkers te ontwerp is dit gewoon nie ekonomies regverdigbaar om sulke toerusting aan
te skaf nie, en ander strategië moet gevind word om ekonomies kompeterend te bly.
Hierdie verslag ondersoek so 'n strategie en die implimentering daarvan.
n Prosedure om gepulsde bipolere transistore vinnig en akkuraat te karakteriseer is ontwikkel en
twee versterkers is met die prosedure ontwerp en gebou. Die versterkers is geverifieer deur hulle
met hulle tradisionele eweknië te vergelyk. Die resultate lyk baie belowend en met n bietjie meer
werk kan die metode waarskynlik ook gebruik word om die transistors buite die toepassings gebied,
soos deur die vervaardigers aangedui, te gebruik.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/16323 |
| Date | 12 1900 |
| Creators | Fourie, Paul |
| Contributors | Van Niekerk, C., 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 | 144 leaves : ill. |
| Rights | University of Stellenbosch |
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