Analysis of SAR Levels in Human Head Tissues for Four Types of Antennas with Portable Telephones

In this paper, a comparative study of several antennas commonly used in portable telephones is investigated. These include a monopole, a helix, a patch and a PIFA antenna. Each one of these structures is modeled and numerically tested using finite-difference time-domain (FDTD) method by using CST Microwave Studio. The testing procedure involves antenna simulation in the proximity of the human head and hand. The behavior of each antenna is evaluated for variable distances from the head geometry (0 - 20 mm). The simulation outputs used as measures for this comparative study include the specific absorption rate (SAR). The computed SAR levels within each of the considered tissues vary for the four antennas under investigation and are within the determined health safety standards. Results suggest that the patch antenna may be the structure of choice when considering safety standards, as its radiation yields the lowest local SAR in the head tissues.

[1]  Nikolaos V. Kantartzis,et al.  A comparative study of the biological effects of various mobile phone and wireless LAN antennas , 2002 .

[2]  A. V. Vorst,et al.  RF/Microwave Interaction with Biological Tissues , 2006 .

[3]  Guidelines Icnirp.  Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz) , 1998 .

[4]  Christos N. Capsalis,et al.  THEORETICAL APPROACH OF THE INTERACTION BETWEEN A HUMAN HEAD MODEL AND A MOBILE HANDSET HELICAL ANTENNA USING NUMERICAL METHODS , 2006 .

[5]  Nobby Stevens,et al.  Comparison of averaging procedures for SAR distributions at 900 and 1800 MHz , 2000 .

[6]  Akimasa Hirata,et al.  Human Head Modeling for Handset Antenna Design at 5 GHz Band , 2005 .

[7]  Yahya Rahmat-Samii,et al.  EM interaction of handset antennas and a human in personal communications , 1995, Proc. IEEE.

[8]  Outi Kivekäs,et al.  Effect of the chassis length on the bandwidth, SAR, and efficiency of internal mobile phone antennas , 2003 .

[9]  J. C. Vardaxoglou,et al.  Simulation and experimental SAR and efficiency study for a dual-band PIFA handset antenna (GSM 900 / DCS 1800) at varied distances from a phantom head , 2004 .

[10]  S. Pisa,et al.  Power absorption and temperature elevations induced in the human head by a dual-band monopole-helix antenna phone , 2001, IMS 2001.

[11]  James C. Lin.  Specific absorption rates (SARs) induced in head tissues by microwave radiation from cell phones , 2000 .

[12]  H. Chuang,et al.  Analysis of a 900/1800-MHz Dual-band Gap Loop Antenna on a Handset with Proximate Head and Hand Model , 2007 .

[13]  Zhinong Ying,et al.  The impact of mobile shell materials on SAR , 2005, 2005 Asia-Pacific Microwave Conference Proceedings.

[14]  C Gabriel,et al.  The dielectric properties of biological tissues: I. Literature survey. , 1996, Physics in medicine and biology.

[15]  A. Hirata,et al.  A Study on Human Body Modeling for the Mobile Terminal Antenna Design at 400 MHZ Band , 2005 .

[16]  Per-Simon Kildal,et al.  Comparison between head losses of 20 phones with external and built-in antennas measured in reverberation chamber , 2002, IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313).

[17]  Y. Rahmat-Samii,et al.  SAR in PIFA handset antenna designs: an overall system perspective , 2005, 2005 IEEE Antennas and Propagation Society International Symposium.

[18]  Mohammad Tariqul Islam,et al.  Design analysis of ferrite sheet attachment for sar reduction in human head , 2009 .