Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FA2
Session:
Number:4FA2-4
Reducing the SAR Values of Mobile Terminal Antennas
Juho Poutanen, Pertti Vainikainen,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
Wireless communications has become an indispensable part in people’s everyday life during the past decades. Examples of the most widely spread wireless applications are mobile phones, wireless internet access, and different Bluetooth devices. As a consequence, the hugely increased amount of electromagnetic radiation everywhere in the environment has increased the concern with possible health risks of wireless devices. In particular, the potential health hazards of mobile phones on human brain have been widely studied. Since a mobile phone is always in a close proximity of the user in a normal talk position, part of the energy radiated by its antenna is unavoidably absorbed by the user. It would be very beneficial if the amount the energy that is absorbed by the user could be reduced, since that would not only reduce any potential health risks but also enhance the total efficiency of the devices; this would improve network coverage and extend battery lifetime. In this paper, we investigate the possibility of reducing the specific absorption rate (SAR) values of a mobile phone antenna by manipulating the dimensions of the display of the phone. The display is modeled by a conducting plate attached to the back side of a coupling element based antenna structure [1]. In addition to the SAR values, the effects of the display on the radiation efficiency and bandwidth potential of the antenna are studied. The results of this paper show that by optimizing the display dimensions the near fields of the antenna can be manipulated, and as a result, the SAR value of the used antenna structure in the user’s head is reduced by up to 46 % at the GSM900 band. At the same time, a 16 %-unit increase in radiation efficiency is obtained.