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Specific Absorption Rate (SAR) simulations in eyewear and Bluetooth communicating devices operating close to the user's head Yuli Álvarez 1, Alvaro de.

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Presentation on theme: "Specific Absorption Rate (SAR) simulations in eyewear and Bluetooth communicating devices operating close to the user's head Yuli Álvarez 1, Alvaro de."— Presentation transcript:

1 Specific Absorption Rate (SAR) simulations in eyewear and Bluetooth communicating devices operating close to the user's head Yuli Álvarez 1, Alvaro de Salles 1, Robert D. Morris 2 & Devra Davis 2 1 Department of Electrical Engineering, Federal University of Rio Grande do Sul – UFRGS, Porto Alegre, Brazil 2 Science, Environmental Health Trust, Jackson, WY, USA The Specific Absorption Rate (SAR) is simulated to four different head models for two approaches that perform variations in the dielectric parameters in the head tissues and compared with the available international recommendations (IEC 62209-2, 2010; ICNIRP, 2009; IEEE C95.1,2005; WHO, 2006; IEEE, 2002 The simulations were performed using SEMCAD- X (the finite difference time domain – FDTD – method) and the frequency used to feed the antennas was 2.45 GHz. Three wearable wireless communication devices were tested: a Bluetooth Handset, which is one of the most economic mobile accessories and two Eyewear Communicating Device which are a representation of the new futuristic vision. Two antennas were used: a monopole antenna and a Planar Inverted F-type (PIFA). Four head models were used: the Specific Anthropomorphic Mannequin (SAM phantom), as well as three realistic models (see Fig.1) of human head (i.e., a 34 years old adult and two children of 10 and 6 years old). The distances between the device and the model are presented in Table I. Four sets of dielectric parameters were used: Adult human Cole-Cole measured by (Gabriel et al. 1996) and three sets measured for different mass/age pigs by (Peyman et al., 2009). Fig1. Heterogeneous models with all the wearable devices: (a) 34 years old model (DUKE, from Virtual Family) (b) 10 years old model (DIEGO from UFRGS) and (c) 6 years old model. (TELLONIUS from Virtual Family) Fig 2. Total psSAR in the Heterogeneous models with all the devices: (PEM: prototype eyewear monopole, PEP: prototype eyewear PIFA and PBP: prototype Bluetooth PIFA). Fig 3. Dosimetric study. psSAR results in 10 years old model with all the devices: (PEM: prototype eyewear monopole, PEP: prototype eyewear PIFA and PBP: prototype Bluetooth PIFA). The higher psSAR levels are simulated in the homogeneous head model, apparently because the distances are closer to the eyewear. According to many authors this can happen since the SAM dielectric parameters were developed to show greater exposure to these type of devices. Also, the eyewear devices antennas are placed below the phantom pinna and not on it as occurs with the headset or a cell phone, then the eyewear antenna are closer to the filling liquid producing higher psSAR values. The psSAR results for all of the three wearable devices are below the (FCC, 1997) and (IEEE, 1998) recommended limits. It is important to remark that these devices are expected to operate many hours everyday very close to the head, and the IEEE, FCC and ICNIRP standards usually adopted in different countries only consider the health effects arising from thermal impacts of short time of exposure REFERENCES FEDERAL COMMUNICATIONS COMMITTEE. Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields. Washington, D. C., 1997. FEDERAL COMMUNICATIONS COMMITTEE. Specific Absorption Rate (SAR) Test Report to Google glass, FCC ID A4R-X1. available in: https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=287362&typ=8374&fcc_id=A4R-X1https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=287362&typ=8374&fcc_id=A4R-X1>. Access in: 7 de Jul. 2014. FEDERAL COMMUNICATIONS COMMITTEE. Tissue Dielectric Properties. available in:. Access in: 15 May 2014.http://www.fcc.gov/fccbin/dielec.sh GABRIEL S. et al. The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz. Physics in Medicine and Biology, [S.l.], v. 41, p. 2251- 2269, 1996.INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS. IEEE 1528: recommended practice for determining the peak spatial-average specific absorption rate (SAR) in the human head from wireless communications devices. New York, 2003.Physics in Medicine and Biology PEYMAN, A. et al. Variation of the dielectric properties of tissues with age: the effect on the values of SAR in children when exposed to walkie-talkie devices. Physics in Medicine and Biology, [S.l.], v. 54, p. 227-241. 2009.Physics in Medicine and Biology SALLES, A. A. A.; BULLA G.; FERNANDEZ, C. E. Electromagnetic absorption in the head of adults and children due to mobile phone operation close to head. Electromagnetic Biology and Medicine, v. 25, n. 4, p. 349-360, Feb. 2006.. Abstract Introduction Results Methods Conclusions Two popular wireless communication devices are considered in this paper. Firstly, the Bluetooth Headset which is one of the most popular mobile accessories and the Eyeware which are a representation of the new futuristic vision. The Specific Absorption Rate (SAR) is simulated for three different head models and compared with the available international recommendations. The first model used is the Specific Anthropomorphic Mannequin (SAM phantom), as well as three realistic models of human head (i.e., a 34 years old adult, a 10 years old boy and a 6 years old boy). The simulations were performed using the finite difference time domain (FDTD) method and the frequency used to feed the antennas was 2.45 GHz.


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