Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: This thesis addresses the complications that are encountered when characterising the performance of differential
microwave LNAs. The predominant sources of noise in electronic circuits are introduced and equivalent
two-port noise models for active devices are derived. Correlation between noise generators are defined by
means of the noise correlation matrix and existing network theory is adapted to include noise analysis of twoport
and multi-port networks. Mixed-mode scattering parameters are introduced in order to define the signal
performance of differential and common-mode propagation in multi-port networks and, by applying the same
theory, the mixed-mode correlation matrix for a three-port dLNA is derived. Furthermore, an expression is derived
for de-embedding the differential noise figure of a three-port dLNA using two single ended measurements.
Two dLNA designs, both incorporating wideband 180°-Hybrid ring couplers, are discussed and the differential
signal and noise performance of the dLNAs are compared to that of their constituent single ended LNAs. / AFRIKAANSE OPSOMMING: Hierdie tesis behandel die komplikasies wat ontwerpers in die gesig staar tydens die karakterisering van mikrogolf
differensiële laeruis versterkers. Die hoof ruisbronne in stroombane word bespreek en ekwivalente
tweepoortnetwerkmodelle vir aktiewe toestelle word afgelei. Korrelasie tussen ruisbronne word gedefnieer
deur middel van ruiskorrelasiematrikse en bestaande tweepoort- en multipoort-netwerkteorie word aangepas
om ruismodelle in te sluit. Weens die feit dat differensiële- en gemene-wyse voortplanting van seine voorkom
in multipoortnetwerke word gemengde-modus S-parameters behandel. Dieselfde teorie maak dit vervolgens
moontlik om die gemengde-modus ruiskorrelasiematriks van ’n drie-poort differensiële laeruis versterker af
te lei. Verder word daar ’n wyse voorgestel waarmee die differensiëleruissyfer van ’n drie-poort differensiële
laeruis versterker vanuit twee enkel ruissyfermetings bereken kan word. Twee differensiële laeruis versterker
ontwerpe, waarvan beide wyeband 180 -differensiaalkoppelaars implementeer, word bespreek en die
differensiëlesein- asook die differensiëleruis-werking word vergelyk met die werking van die omsluite ongebalanseerde
laeruis versterkers.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/18063 |
| Date | 12 1900 |
| Creators | Prinsloo, David Schalk Van Der Merwe |
| Contributors | Meyer, P., De Villiers, D. I. L., 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 | Unknown |
| Type | Thesis |
| Format | 138 p. : ill. |
| Rights | Stellenbosch University |
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