Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365086
Title: Design and comparative performance evaluation of novel mobile handset antennas and their radiative effects on users
Author: Panayi, Petros K.
ISNI:       0000 0001 3466 3433
Awarding Body: University of Glamorgan
Current Institution: University of South Wales
Date of Award: 2000
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Abstract:
The beginning of the 21 st century is characterised, among others, by the evolution in telecommunications. The rapid growth of mobile communications and the variety of applications proposed for the third generation (3G) systems require long operation time, low weight and cost for terminals, as well as improved link quality. For this reason a good efficiency and low profile antennas with low absorption losses by the user are desirable. The Planar Inverted-F Antenna (PIFA) is shown to result into low SAR values and high efficiency when operating in the proximity of the user. Despite these advantages, PIFA is also characterised by narrow bandwidth that limits its practical use. The first part of this work is dedicated to the measurements and evaluation of the radiation characteristics of the PIFA and other wire antennas both in the near and far fields. In addition, novel methods of PIFA tuning are presented. These include the repositioning of the shorting pin and modification of its capacitance. By using these techniques, the effective bandwidth of the PIFA can be increased to satisfy the GSM900 and DCS 1800 system bandwidth requirements. Dual-band and electronically tuned PIFA prototypes are also included. The effects of the handset size on the mass averaged Specific Absorption Rate (SAR), and antenna efficiency are investigated. The appropriate choice of handset can result in up to 30%-reduced peak SAR. The computed SAR values from PIFA are compared with those resulting from the use of a handset equipped with quarter wavelength monopole antenna. A new measure referred to as the 3dB SAR volume is proposed. This measure provides better understanding of the absorbed power distribution in the operator's head. Results obtained in the course of study show that low profile handset antennas, such as the PIFA, present in addition to dual resonance and low reflection losses, reduced SAR values, high efficiency and low 3dB SAR volume. Finally, SAR and 3dB SAR volume values from simulations on 5- and 10- years old child head models are compared with their equivalents for adult models from which appropriate conclusions are drawn.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.365086  DOI: Not available
Keywords: Mobile communications ; low profile antennas ; Planar Inverted-F Antenna (PIFA) ; radiation characteristics ; bandwidth ; Specific Absorption Rate (SAR)
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