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Development of a low phase noise microwave voltage controlled oscillator

dc.contributor.advisorDe Swardt, J. B.en_ZA
dc.contributor.advisorVan der Walt, P. W.en_ZA
dc.contributor.authorVermaak, Elrienen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
dc.date.accessioned2008-11-25T06:39:37Zen_ZA
dc.date.accessioned2010-06-01T08:40:00Z
dc.date.available2008-11-25T06:39:37Zen_ZA
dc.date.available2010-06-01T08:40:00Z
dc.date.issued2008-12
dc.identifier.urihttp://hdl.handle.net/10019.1/2073
dc.descriptionThesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008.
dc.description.abstractThe topic for this project entailed the development of a ‘Low Phase Noise – Microwave – Voltage Controlled Oscillator’ for use in radar applications. First of all, a low phase noise oscillator was designed. In order to minimise the phase noise of the oscillator, a high-Q, transmission line – cavity resonator was developed. By derivation it was confirmed that an optimal point for minimum phase noise does exist. The latter was done by evaluating the equation for the output power spectral density of the oscillator phase noise (as defined by Leeson’s Phase Noise Model) at its minimum point. Subsequently, the amount of power that needed to be dissipated inside the resonator could be compared to that dissipated in the source and the load. This identified the amount of coupling to the resonator allowed, assuring minimum phase noise. Since a specific amount of coupling to the resonator was sought after, it had to be practically feasible. Therefore several coupling techniques were investigated to ensure the most user-friendly way of tuning the amount of coupling to the resonator, and hence easily reaching the optimum point of minimum phase noise. After successful completion of the low phase noise oscillator design, it was modified for voltage controlled oscillator (VCO) use by means of variable tuning diodes. These varactor diodes were situated inside the cavity of the resonator. Again the most suitable position to place the diodes had to be determined. The latter was done through considerably detailed transmission line theory; where the loaded Q, the tuning bandwidth (amount of change in frequency reached) and the amount of power dissipated inside the resonator were measured against each other. By means of the necessary phase noise measurements, it was confirmed that in order to keep the phase noise to a minimum, the tuning bandwidth had to be kept small and the amount of power dissipated inside the resonator maximised; so as to keep the overall loaded Q-value of the circuit as high as possible.en_ZA
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.subjectCavity resonatoren_ZA
dc.subjectMicrowaveen_ZA
dc.subjectPhase noiseen_ZA
dc.subjectTheses -- Electronic engineeringen_ZA
dc.subjectDissertations -- Electronic engineeringen_ZA
dc.subject.lcshVoltage-controlled oscillatorsen_ZA
dc.subject.lcshOscillators, Microwave -- Design and constructionen_ZA
dc.titleDevelopment of a low phase noise microwave voltage controlled oscillatoren_ZA
dc.typeThesisen_ZA
dc.rights.holderStellenbosch University


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