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Development of a low phase noise microwave voltage controlled oscillator

Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008.

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Main Author: Vermaak, Elrien
Other Authors: De Swardt, J. B.
Format: Thesis
Language:English
Published: Stellenbosch : Stellenbosch University 2008
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access_status_str Open Access
author Vermaak, Elrien
author2 De Swardt, J. B.
author_browse De Swardt, J. B.
Vermaak, Elrien
author_facet De Swardt, J. B.
Vermaak, Elrien
author_sort Vermaak, Elrien
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008.
format Thesis
id oai:scholar.sun.ac.za:10019.1/2073
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:43:23.129Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2008
publishDateRange 2008
publishDateSort 2008
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/2073 Development of a low phase noise microwave voltage controlled oscillator Vermaak, Elrien De Swardt, J. B. Van der Walt, P. W. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Cavity resonator Microwave Phase noise Theses -- Electronic engineering Dissertations -- Electronic engineering Voltage-controlled oscillators Oscillators, Microwave -- Design and construction Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. The 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. 2008-11-25T06:39:37Z 2010-06-01T08:40:00Z 2008-11-25T06:39:37Z 2010-06-01T08:40:00Z 2008-12 Thesis http://hdl.handle.net/10019.1/2073 en Stellenbosch University application/pdf Stellenbosch : Stellenbosch University
spellingShingle Cavity resonator
Microwave
Phase noise
Theses -- Electronic engineering
Dissertations -- Electronic engineering
Voltage-controlled oscillators
Oscillators, Microwave -- Design and construction
Vermaak, Elrien
Development of a low phase noise microwave voltage controlled oscillator
title Development of a low phase noise microwave voltage controlled oscillator
title_full Development of a low phase noise microwave voltage controlled oscillator
title_fullStr Development of a low phase noise microwave voltage controlled oscillator
title_full_unstemmed Development of a low phase noise microwave voltage controlled oscillator
title_short Development of a low phase noise microwave voltage controlled oscillator
title_sort development of a low phase noise microwave voltage controlled oscillator
topic Cavity resonator
Microwave
Phase noise
Theses -- Electronic engineering
Dissertations -- Electronic engineering
Voltage-controlled oscillators
Oscillators, Microwave -- Design and construction
url http://hdl.handle.net/10019.1/2073
work_keys_str_mv AT vermaakelrien developmentofalowphasenoisemicrowavevoltagecontrolledoscillator