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Investigation, design and implementation of circular-polarised antennas for satellite mobile handset and wireless communications. Simulation and measurement of microstrip patch and wire antennas for handheld satellite mobile handsets and investigations of polarization polarity, specific absorption rate, and antenna design optimization using genetic algorithms.

Khalil, Khaled
Publication Date
2010-06-01T15:29:04Z
End of Embargo
Supervisor
Abd-Alhameed, Raed
Excell, Peter S.
Keywords
Quadrifilar Spiral Antenna (QSA), Quadrifilar Helical Antenna (QHA), Microstrip patch antennas, Circular polarization, Specific Absorption Rate (SAR), Conical beam, Genetic Algorithms (GA), Satellite mobile communication, Wireless sensor networks
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Creative Commons License
The University of Bradford theses are licenced under a Creative Commons Licence.
Peer-Reviewed
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Accepted for publication
Institution
University of Bradford
Department
School of Engineering, Design and Technology
Awarded
2009
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Abstract
The objectives of this research work are to investigate, design and implement circularly-polarized antennas to be used for handheld satellite mobile communication and wireless sensor networks. Several antennas such as Quadrifilar Spiral Antennas (QSAs), two arm Square Spiral and stripline or coaxially-fed microstrip patch antennas are developed and tested. These antennas are investigated and discussed to operate at L band (1.61-1.6214GHz) and ISM band (2.4835-2.5GHz) A substantial size reduction was achieved compared to conventional designs by introducing special modifications to the antenna geometries. Most of the antennas are designed to produce circularly-polarized broadside-beam except for wireless sensor network application a circularly-polarized conical-beam is considered. The polarization purity and Specific Absorption Rate (SAR) of two dual-band antennas for satellite-mobile handsets next to the human head are investigated and discussed, using a hybrid computational method. A small distance between the head and the handset is chosen to highlight the effects of the relatively high-radiated power proposed from this particular antenna. A Genetic Algorithm in cooperation with an electromagnetic simulator has been introduced to provide fast, accurate and reliable solutions for antenna design structures. Circularly-polarized quadrifilar helical antenna handset and two air-dielectric microstrip antennas were studied. The capabilities of GA are shown as an efficient optimisation tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to designated specifications. The results in terms of the antenna size and radiation performance are addressed, and compared to measurements and previously published data.
URI
http://hdl.handle.net/10454/4319
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Type
Thesis
Qualification name
PhD
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