zastosowania elektromagnetyzmu w nowoczesnych ... - PTZE

30
XVIII Sympozjum PTZE, Zamość 2008
l is shown in Fig.1. The spheroid is an isotropic lossy dielectric. Time-harmonic fields with
the time-dependence e jωt as a uniform plane wave are suppressed. The external medium is
assumed to be free space. The relative permittivity ε’-jε” and the conductivity of tissue
depend on frequency. European Standard EN-50361 establishes values of ε, γ for fantom
liquid at mobile frequency band 300 – 3000 MHz to be used in SAR calculations. The
simulations were done for GSM frequencies used in mobile telephony: 900 MHz and 1800
MHz. The rms value of the electric field strength incident was 61,4 V/m. The values of the
SAR were calculated using semi-analytical method. The method of calculations was described
in [3]. The SAR for different configuration have been calculated. The spheroidal body
dimensions taken into account are corresponding to dimensions of human body.
Results
Regarding statistical data avaible on human height and body mass 18 models were
considered. The conductivity and permeability of tissues of young organism are higer
comparing to the adult organism. In Figure 2 values of SAR at polarization H and two
frequencies have been presented in relation of longer axis l of the body. The variation of the
SAR at 900MHz is observed to be rather small. The SAR has larger value at larger frequency
and the values of SAR in the body depend on dimensions of the body. The values of the
SAR are higer for young person and they correspond to higer values of conductivity and
permeability of tissues of young organism comparing to the adult organism .
References
SAR [W/kg]
0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.1
0.08
1800 MHz
900 MHz
0.06
60 80 100 120
l [cm]
140 160 180
Fig. 2. Calculated values of SAR at polarization H.
[1] Ciosk K., Krawczyk A., Kubacki R.: The influence of the electromagnetic wave parameters on SAR
coefficient, in: Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (eds.
A.Krawczyk, S.Wiak, X.M.Lopez-Fernandez), IOS Press, Amsterdam 2006
[2] Ciosk K., Krawczyk A: The influence of the electromagnetic wave frequency on SAR in biological object.,
EHE’06, Madeira, pp.2.97-2.100
[3] Ciosk, A. Krawczyk, R. Kubacki, The comparison of phantom model and simulation results in SAR
analysis , in: Computer Engineering in Applied Electromagnetism (eds. S. Wiak, A. Krawczyk, M. Trlep),
Springer, 2005