Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This thesis presents the design, construction and measurement of two wide-band LNA’s for the
SKA-Mid range (350-1200 MHz). The first wide-band LNA involves the investigation of classic
low noise amplifier techniques, which includes basic noise theory, stability analysis, feedback
design and the development of sophisticated matching techniques for ultra wide-band performance.
Final measurements show a flat gain response equal to 19 dB, with a noise figure of 1.5
dB and an output return loss of 10 dB across the entire bandwidth.
A multi-path cascading concept is introduced for the second low noise amplifier design, which
aims to connect two single frequency amplifiers in parallel to operate from 500 to 700 MHz. The
design process involves several optimization schemes to realise the matching networks for the
cascaded topology and the noise performance of the device was confirmed by using multi-port
noise theory. The prototype presents significant bandwidth improvements compared to a single
frequency LNA design. Excellent agreement between the simulation and measurement were
obtained with a flat gain response of 20 dB across a 2:1 bandwidth, with a low noise figure of
0.95 dB and an output return loss of 13 dB across the operation bandwidth of 400 to 800 MHz. / AFRIKAANSE OPSOMMING: Hierdie tesis behandel die ontwerp, konstruksie en meting van twee wyeband laeruis versterkers
vir die SKA - Mid reeks (350–1200 MHz). Die eerste wyeband laeruis versterker, ondersoek
klassieke laeruis versterker tegnieke wat insluit basiese ruisteorie, stabiliteit analise, terugvoerontwerp
en die ontwikkeling van gevorderde aanpassingstegnieke vir ultra wyeband werkverrigting.
Finale metings het ’n plat aanwins van 19 dB, met ’n ruisfiguur van 1.5 dB en ’n uittree-refleksie
koëffisiënt van -10 dB oor die hele bandwydte vertoon.
’n Multi-pad konsep word bekend gestel vir die tweede laeruis versterker. Die ontwerp het twee
enkel frekwensie laeruis versterkers in parallel verbind om vanaf 500 tot 700 MHz te werk. Die
ontwerp proses bevat verskeie optimalisering skemas om die aanpassings netwerke vir die kaskade
topologie te realiseer. Die ruissyfer van die versterker is bevestig deur die gebruik van multi-pad
ruisteorie. Die prototipe het beduidende bandwydte verbeterings vertoon in vergelyking met ’n
enkel frekwensie versterker ontwerp. ’n Uitstekende ooreenkoms tussen die simulasie en meting
was verkry met ’n plat aanwins van 20 dB oor ’n 2:1 bandwydte, met ’n laeruisfiguur van 0.95
dB en ’n uittree-refleksie koëffisiënt van -13 dB oor die bandwydte van 400-800 MHz.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/97058 |
| Date | 03 1900 |
| Creators | Botes, Dewald Alewyn |
| Contributors | Meyer, Petrie, 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 | 119 pages : illustrations |
| Rights | Stellenbosch University |
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