Wide band, low-noise amplifiers for the mid-range SKA

Botes, Dewald Alewyn (2015-03)

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.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/97058
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