Title page for ETD etd-10212009-182412

Document Type Master's Dissertation
Author Steyn, Johanna Mathilde
Email jjmsteyn@gmail.com
URN etd-10212009-182412
Document Title A dual-band dual-polarized antenna for WLAN applications
Degree MEng
Department Electrical, Electronic and Computer Engineering
Advisor Name Title
Prof J Joubert Co-Supervisor
Prof J W Odendaal Supervisor
  • kompakte struktuur
  • direktiewe stralingspatrone
  • hoŽ wins
  • WLAN
  • wye bandwydte
  • dual-band
  • dual-polarized
  • dual-band dual-polarized
  • wide bandwidths
  • single-dielectric-layer substrate
  • high gain
  • end-fire radiation pattern
  • compact structure
  • IEEE 802.11a WLAN standards
  • DLAN
  • dubbel-band
  • dubbel-polarisasie
  • dubbel-band dubbel-gepolariseerd
  • enkel-diŽlektriese-laag substraat
  • IEEE 802.11b
  • IEEE 802.11a WLAN standaarde
Date 2009-09-02
Availability unrestricted

The recent growth in the ambit of modern wireless communication and in particular WLAN (Wireless Local Area Network) systems has created a niche for novel designs that have the capacity to send and/or receive arbitrary orthogonal polarizations. The designs should also be able to support dual-band functionality, while maintaining a compact structure. The first aim of this dissertation was thus to develop a dual-band single radiating element that can cover the 2.4 GHz (2.4 Ė 2.484 GHz) band and the 5.2 GHz (5.15 Ė 5.85 GHz) band for the IEEE 802.11b and IEEE 802.11a WLAN standards respectively. Dual-frequency elements such as stacked-, notched- and dichroic patches have been considered, but due to the size and the high cross-polarization levels associated with these designs, the design process was propelled towards various dipole and monopole configurations. The attributes of various designs were compared, where the double Rhombus antenna pregnant with dual-band and dual-polarization potential was used as basis in the development of the DBDP (Dual-Band Dual-Polarized) antenna design. The single-element design exhibited wide bandwidths, good end-fire radiation patterns and relatively high gain over the 2.4/5.2 GHz bands. A two-element configuration was also designed and tested, to firstly increase the gain of the configuration and secondly to facilitate the transformation of the dipole design into a dual-polarized configuration.

The second aim of this dissertation was to develop a dual-polarized array, while making use of only two ports, each pertaining to a specific polarization and to implement the design on a single-dielectric-layer substrate. Most dual-polarized structures such as circular, square and annular microstrip antenna designs only support one band, where multi-dielectric-layer structures are the norm. The disadvantages associated with multi-layered designs, such as fabrication difficulties, high costs, high back lobes and the size of the arrays, further supported the notion of developing an alternative configuration. The second contribution was thus the orthogonal interleaving of the two-element array configurations, to address the paucity of single-dielectric-layer dual-band dual-polarized designs that can be implemented with only two ports. This design was first developed and simulated with the aid of the commercial software package CST Microwave Studioģ and the results were later corroborated with the measured data obtained from the Compact Antenna Range at the University of Pretoria.

AFRIKAANS : Die onlangse groei in die area van moderne draadlose kommunikasie en met spesifieke verwysing na DLAN (Draadlose Lokale Area Netwerk) stelsels, het Ďn nis vir nuwe ontwerpe geskep. Daar word van hierdie nuwe ontwerpe die kapasiteit verlang om verskeie ortogonale polarisasies te stuur en/of te ontvang in samewerking met dubbel-band eienskappe, terwyl Ďn kompakte struktuur nogsteeds aandag moet geniet. Die eerste doel met hierdie verhandeling was dus die ontwikkeling van Ďn dubbel-band enkel stralingselement wat instaat is om die 2.4 GHz (2.4 Ė 2.484 GHz) band en die 5.2 GHz (5.15 Ė 5.85 GHz) band wat as die IEEE 802.11b en die IEEE 802.11a DLAN standaarde respektiewelik bekend staan, te bedek. Dubbel-frekwensie elemente soos onder andere die gepakte-, merkkepie- en dichromatiese strook antenne was as moontlike oplossings ondersoek, maar die grootte en hoŽ kruispolarisasie wat gewoonlik met hierdie ontwerpe gepaard gaan, het die ontwerpsproses in die rigting van verskeie dipool en monopool konfigurasies gestoot. Die aantreklike eienskappe van die verskeie ontwerpe was met mekaar vergelyk, waar die dubbel Rhombus antenna, verwagtend met dubbel-band dubbel-polarisasie potensiaal, as basis vir die ontwikkeling van die DBDP (Dubbel-Band Dubbel-Polarisasie) antenna ontwerp gebruik is. Die enkelelementontwerp het wye bandwydtes, goeie direktiewe stralingspatrone en relatiewe hoŽ wins oor die 2.4/5.2 GHz bande geopenbaar. Die twee-element konfigurasies was ook ontwerp en getoets om eerstens die wins van die konfigurasie te verhoog en tweedens om die transformasie na Ďn dubbel-gepolariseerde konfigurasie te fassiliteer.

Die tweede doel van hierdie verhandeling was om Ďn dubbel-gepolariseerde elementopstelling met net twee poorte te ontwikkel, waar elkeen verantwoordelik is vir Ďn spesifieke polarisasie, en te implementeer op Ďn enkel-diŽlektriese-laag substraat. Die meeste dubble-polarisasiestrukture, soos onder andere die sirkulÍre-, vierkantige- en ringvormige antenne ontwerpe, kan net een frekwensieband onderhou en word gewoonlik met behulp van meervoudige-diŽlektriese-laagstrukture geimplementeer. Die negatiewe eienskappe soos onder andere die vervaardigingsmoeilikhede, hoŽ kostes, hoŽ teruglobbe en die grootte van die meervoudige-elementopstellings wat aan hierdie meervoudige-diŽlektriese-laagontwerpe behoort, het verder die denkbeeld van Ďn alternatiewe konfigurasie bekragtig. Die tweede hoofbydrae was dus die ortogonale insleuteling van die twee-element meervoudige-elementopstelling konfigurasies om die geringheid van enkel-diŽlektriese-laag dubbel-band dubbel-polarisasie ontwerpe, wat net met twee poorte geÔmplementeer kan word, te adresseer. Hierdie ontwerp was eers met behulp van die kommersiŽle sagtewarepakket CST Microwave Studioģ ontwikkel en gesimuleer, waarna die resultate bevestig was deur meetings by die Kompakte Antenna Meetbaan van die Universiteit van Pretoria.

©2009, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Steyn, JM 2009, A dual-band dual-polarized antenna for WLAN applications, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-10212009-182412/ >


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