The design and implementation of microwave receiver front end components

Netshifhire, Vhudilangi Patrick (2005-12)

Thesis (MScEng)--Stellenbosch University, 2005.

Thesis

ENGLISH ABSTRACT: Different types of RF and Microwave receiver systems architectures are investigated. The superheterodyne receiver characteristics are studied qualitatively. A three components system (LNA, Mixer and VeO) is selected and the components are first measured individually, and then measured as a single system. A mono filar axial mode helix antenna is designed, simulated using FEKO and constructed. A narrow band interdigital bandpass filter is designed using the capacitance network and its transformation, and it is simulated using two different simulation packages, eST Microwave Studio and AWR Microwave Office. Two filter prototypes are fabricated using cylindrical rods. An open circuited microstrip resonator oscillator is designed and implemented through the negative resistance method. Its performance is verified using the harmonic balance simulator in AWR MWO. A single balanced mixer is designed and implemented using 1800 hybrid junction (rat-race) and it is also fabricated using microstrip transmission line technology. All designed components performed well in comparison to their predicted performance. The LNA and three of the designed components (Filter, Oscillator and a Mixer) are connected together and characterized as a single four block system. The system performed well except for the IF signal which shift to a lower frequency due to oscillator load pulling.

AFRIKAANSE OPSOMMING: Die argitektuur van verskeie RF en Mikrogolf ontvanger stelsels word ondersoek. Die "superheterodyne" ontvanger eienskappe is kwalitatief bestudeer. 'n Stelsel wat uit drie komponente bestaan (LNA, Menger en VeO) is bestudeer. Die individuele komponente is eers gemeet en daarna die stelsel as 'n eenheid. 'n "Mono filar" aksiale modus heliks antenna is ontwerp, gesimuleer met FEKO en gebou. Verder is 'n nouband inter-digitale banddeurlaat filter ontwerp met behulp van die kapasitiewe network metode en sy transformasie. Hierdie ontwerp is gesimuleer deur van twee verskillende sagteware pakette gebruik te maak, naamlik eST Microwave Studio en AWR Microwave Office. Twee filter prototiepes is gebou met silindriese stafies. 'n Oopgeslote mikrostrook ossilator is ontwerp en geimplementeer deur negatiewe weerstand te gebruik. Die stelsel se prestasie is bevestig deur gebruik te maak van 'n harmoniese balans simulator in AWR MWO. Verder is 'n enkelbalans menger ontwerp en geimplimenteer via 'n 1800 hibriede verbinding ("rat-race"). Hierdie menger is gebou met mikrostrook transmisielyn. Al die ontwerpte komponente werk goed in vergelyking met die voorspelde resultate. Die LNA, filter, ossilator en menger word gekoppel en gekarakteriseer as 'n vier blok stelsel. Die stelsel werk goed behalwe vir 'n skuif in die IF-sein by laer frekwensies a.g.v. belasting.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/50473
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