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A low noise PLL-based frequency synthesiser for X-band radar

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

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Main Author: Moes, Henderikus Jan
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 Moes, Henderikus Jan
author2 De Swardt, J. B.
author_browse De Swardt, J. B.
Moes, Henderikus Jan
author_facet De Swardt, J. B.
Moes, Henderikus Jan
author_sort Moes, Henderikus Jan
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:10019.1/2390
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:40:58.109Z
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:10019.1/2390 A low noise PLL-based frequency synthesiser for X-band radar Moes, Henderikus Jan De Swardt, J. B. Van der Walt, P. W. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Theses -- Electrical and electronic engineering Dissertations -- Electrical and electronic engineering Doppler radar Phase-locked loops Electrical and Electronic Engineering Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. This thesis discusses the design, development and measured results of a phase-locked loop based frequency synthesiser for X-band Doppler radar. The objective is to obtain phase noise comparable or lower than that typically achieved with direct analogue frequency synthesis techniques. To meet this objective, a theoretical study of the noise contributions of individual components of the synthesiser and their effect on the total phase noise within and outside the loop bandwidth of the PLL is performed. The effect of different phase margins on the closed-loop frequency response of the PLL, and hence the total phase noise, is investigated. Based on the results, an optimal phase-frequency detector reference frequency, loop bandwidth, adequate phase margin, and suitable components are chosen for optimal phase noise performance. The total phase noise at the output of the synthesiser is calculated and it is shown that the phase noise specification can be met. A significant part of this thesis is devoted to the design, modelling and characterisation of a frequency multiplier, as well as to a combline and interdigital bandpass filter required for the frequency synthesiser. In the first case, a piecewise linear circuit model is used to model the behaviour of the nonlinear multiplier circuit. Fourier theory is used to calculate the large-signal driving point input and output impedances of the nonlinear circuit, enabling the computation of the circuit elements for the input and output matching networks. The measured response of the frequency multiplier under various different operating conditions is presented and discussed. The design of the microwave bandpass filters is based on the theory of coupling and external quality factors. To aid in the verification and optimisation of the design, a software simulation tool is used. The presented S-parameter measurements of the filters show how well the theory matches with what is obtained in practice. The measured spectral and phase noise response of various components comprising the synthesiser, are discussed. These measurements provide insight into the response of individual components under different operating conditions and show the behaviour of important subsystems of the synthesiser. The thesis culminates in the presentation of the measured phase noise of the complete synthesiser. It is shown how well the measured phase noise correlates with the calculated phase noise. In addition, the measured spectral content and transient behaviour of the synthesiser are investigated and discussed. High power spurious components at some output frequencies are indentified and reduced. The feasibility of using the developed prototype phase-locked loop based frequency synthesiser for coherent X-band Doppler radar is discussed and demonstrated. 2008-08-12T09:20:53Z 2010-06-01T08:47:43Z 2008-08-12T09:20:53Z 2010-06-01T08:47:43Z 2008-03 Thesis http://hdl.handle.net/10019.1/2390 en Stellenbosch University application/pdf Stellenbosch : Stellenbosch University
spellingShingle Theses -- Electrical and electronic engineering
Dissertations -- Electrical and electronic engineering
Doppler radar
Phase-locked loops
Electrical and Electronic Engineering
Moes, Henderikus Jan
A low noise PLL-based frequency synthesiser for X-band radar
title A low noise PLL-based frequency synthesiser for X-band radar
title_full A low noise PLL-based frequency synthesiser for X-band radar
title_fullStr A low noise PLL-based frequency synthesiser for X-band radar
title_full_unstemmed A low noise PLL-based frequency synthesiser for X-band radar
title_short A low noise PLL-based frequency synthesiser for X-band radar
title_sort low noise pll based frequency synthesiser for x band radar
topic Theses -- Electrical and electronic engineering
Dissertations -- Electrical and electronic engineering
Doppler radar
Phase-locked loops
Electrical and Electronic Engineering
url http://hdl.handle.net/10019.1/2390
work_keys_str_mv AT moeshenderikusjan alownoisepllbasedfrequencysynthesiserforxbandradar
AT moeshenderikusjan lownoisepllbasedfrequencysynthesiserforxbandradar