Thesis (MScEng) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT: The development of a small, cost effective short range FM-CW radar as well as the design
and optimization of a double helix antenna is discussed. The FM-CW radar operates at Sband
(2450 - 2550 MHz) and is limited at a maximum transmitted power of 5 dBm. The
system is required to detect reflections from objects up to a 30 m range. This was made
possible largely by the effective high gain antenna design and improved system isolation
between the transmitted and received signals.
The complete design process from fundamental requirements, through various simulations
and system analysis to the final electronic circuit is discussed. The design was also built and
measured in the laboratory and initial field measurements were taken. The following aspects
were considered:
Relation between the beat frequency and various FM-CW radar system
parameters based on the theory, preliminary measurements and simulations.
Radar component assessment and design.
Design of a low cost Lange coupler that isolates the system's transmit and
receive signals, which operates as a 90° hybrid and is used to feed a dual-fed
circularly polarized patch antenna.
A circularly polarized patch antenna and double helix antenna were designed,
built and measured in an anechoic chamber. The antennas were implemented
in the final radar system and compared on the basis of their contribution to the
system's performance.
Integrating the final radar system on a circular 60 mm diameter PCB with a
double helix antenna mounted on top.
The final radar system is able to measure range up to 40 m and meets all the design
requirements. The signal processing of the measured beat frequency, however, can be taken
further. / AFRIKAANSE OPSOMMING: Die ontwikkeling van 'n klein, koste effektiewe kort-afstand FM-CW radar, sowel as die
onwerp en optimalisering van 'n dubbele heliks-antenna word bespreek. Die FM-CW radar
werk by S-band (2450 - 2550 MHz) en is beperk tot 'n maksimum uitsaaidrywing van 5 dBm.
Van die stelsel word vereis om weerkaatsings van voorwerpe tot op 'n afstand van 30 m waar
te neem. Dit is grootliks moontlik gemaak deur die hoë aanwins antenna-ontwerp en
verbeterde isolasie tussen die stelsel se uitsaai- en ontvangseine.
Die volledige ontwerpsproses van die fundamentele vereistes af tot die finale elektroniese
stroombaan word bespreek. Verskeie simulasies andstelselanalises is gebruik om die finale
FM-CW radar te realiseer. Die ontwerp is vervolgens in die laboratorium gebou en gemeet en
aanvangsveldmetings is geneem. Die volgende aspekte is in nagevors:
Verband tussen die puls-frekwensie en verskeie FM-CW radar stelselparameters
gebaseer op die teorie, inleidende metings en simulasies.
Ontleding van verskeie radarkomponente en -stelselontwerp.
Ontwerp van 'n lae koste Lange-koppelaar met die doelom die stelsel se
uitsaai- en ontvangseine te isoleer. Die Lange-koppelaar dien as 'n 90° hibriede
wat gebruik word om 'n dubbele-voer sirkulêr gepolariseerde mikrostrookantenna
aan te dryf.
Verder is 'n sirkulêr gepolariseerde mikrostrook-antenna en 'n dubbele heliksantenna
ontwerp en opgemeet in 'n anarqoïese kamer. Beide antennas is
geïmplimenteer in die finale radarstelsel en is vergelyk op grond van hulle rol in
die stelsel se funksionering.
Die finale stelsel is geïntegreer en gebou op 'n ronde 60 mm deursnit PCB met
'n dubbele helix-antenna bo-op gemonteer.
Die finale radarstelsel kan afstand tot op 40 meter bepaal en voldoen aan al die gestelde
vereistes. Seinverwerking van die gemete puls-frekwensie kan nog verder ontwikkel word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/50132 |
| Date | 04 1900 |
| Creators | Kellerman, Robert A. |
| Contributors | De Swardt, J. B., Stellenbosch University. Faculty of Engineering . Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 118 p. : ill. |
| Rights | Stellenbosch University |
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