Estimation Formulas for the Specific Absorption Rate in Humans Exposed to Base-Station Antennas

Friden

et al. 2014

Bioelectromagnetics

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In this paper, different methods for practical numerical radio frequency (RF) exposure compliance assessments of radio base station (RBS) products are investigated. Both multi-band base station antennas and antennas designed for multiple-input multiple-output (MIMO) transmission schemes are considered. For the multi-band case, various standardized assessment methods are evaluated in terms of resulting compliance distance with respect to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels and basic restrictions. Both single frequency and multiple frequency (cumulative) compliance distances are determined, using numerical simulations for a mobile communication base station antenna transmitting in four frequency bands between 800 MHz and 2600 MHz. The assessments are conducted in terms of the root-mean squared electromagnetic field, the whole-body averaged SAR and the peak 10g averaged SAR. In general, assessments based on peak field strengths are found to be less computationally intensive but lead to larger compliance distances than spatial averaging of electromagnetic fields used in combination with localized SAR assessments. As long as adult exposure is considered, the results also indicate that even shorter compliance distances are obtained by using assessments based on localized and wholebody SAR. Numerical simulations, using base station products employing multiple-input multipleoutput (MIMO) transmission schemes, are performed as well and are in good agreement with reference measurements. The applicability of various field combination methods for correlated exposure is investigated, and best estimate methods are proposed. It is also shown, that field combining methods generally considered as conservative may be used to efficiently assess compliance boundary dimensions of single-and dual-polarized multicolumn base station antennas with only minor increases in compliance distances. Key words: Mobile communication; Electromagnetic field exposure; EMF compliance; SpecificAbsorption Rate; MIMO; Multi-standard radio base station; Multi-band radio base station. INTRODUCTIONBefore radio base station (RBS) products are placed on the market, their manufacturers conduct electromagnetic field (EMF) product compliance assessments to make sure that the equipment fulfills relevant regulatory requirements on EMF exposure. The purpose of these assessments is to determine compliance boundaries outside of which the radiofrequency (RF) EMF exposure is below applicable exposure limits. The most widely adopted exposure limits are specified by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) [ICNIRP, 1998]. For frequencies between 10 MHz to 10 GHz, including the frequency range used for mobile communications, the fundamental dosimetric quantity is the specific absorption rate (SAR). SAR corresponds to the rate of dissipated energy per unit mass within the exposed body due to the incident electromagnetic fields. Assessing exposure with respect to the basic re...

supporting

confidence: 40%

“…The dimensions of this phantom were derived to obtain conservative whole-body SAR results for 95% of the adult population [Gosselin et al, 2011]. Also for spatial peak SAR, conservative results are obtained [IEC, 2011].…”

Section: Product Compliance Assessmentsmentioning

confidence: 99%

Radio frequency electromagnetic field compliance assessment of multi‐band and MIMO equipped radio base stations

Thors

Friden

et al. 2014

Bioelectromagnetics

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“…To gain more insight in the curves , a fit using equation (5) propagation is expected, leading to a quadratic decay of SAR values with distance [Cicchetti et al, 2004; Thors et al, 2008;Gosselin et al, 2011]. The different simulation results used to determine the cumulative compliance distance are situated in both the region of cylindrical propagation and the spherical propagation region, depending on the frequency and distance from the antenna [Thors et al, 2008].…”

Section: Discussionmentioning

confidence: 99%

Compliance boundaries for multiple‐frequency base station antennas in three directions

Vermeeren

Kurup

et al. 2013

Bioelectromagnetics

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“…In order to protect them from possible RF induced health effects, compliance boundaries based on the ICNIRP basic restrictions (BR) on whole body averaged specific absorption rate (SAR), 10g localized SAR and electric field (reference levels (RL)) [1] are determined. Earlier studies have studied these quantities around several BSAs [2]- [5]. In other studies compliance boundaries have already been studied for GSM (900 MHz) [3], [6] and other frequencies [4], [5], [7], using generic BSAs or dipole arrays.…”

Section: Introductionmentioning

confidence: 99%

“…Earlier studies have studied these quantities around several BSAs [2]- [5]. In other studies compliance boundaries have already been studied for GSM (900 MHz) [3], [6] and other frequencies [4], [5], [7], using generic BSAs or dipole arrays. The influence of a reflective environment has also been studied [2], [8].…”

Section: Introductionmentioning

confidence: 99%

Compliance boundaries for LTE base station antennas at 2600 MHz

2012 6th European Conference on Antennas and Propagation (EUCAP)

Vermeeren

Kurup

et al. 2012

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Abstract-Compliance boundaries and allowed output powers based on on the whole body averaged specific absorption rate (SAR) and the 10 g averaged SAR in both the limbs and the head and trunk and the root mean squared electrical field, are determined for three orientations regarding three base station antennas (BSAs) emitting at 2600 MHz. The ICNIRP basic restrictions and reference levels for both the general public and occupational exposure, are used to determine these compliance boundaries. FDTD simulations are carried out using the virtual family male and CAD models of the three antennas. The results for the different basic restrictions and reference levels are compared and we observed that the reference levels are not conservative when the antenna is only partially radiating. The simulation results show that the basic restriction on the 10g averaged SAR in the head and trunk of the body determines the compliance boundaries at lower antenna powers. Combined compliance distances, which ensure compliance with all reference levels and basic restrictions, have been determined for every frequency. The errors on the estimated allowed power are used for an uncertainty analysis for the compliance distances.