TC34_SC2 - SAR evaluation - numerical techniques

jafar keshvari

This standard describes the concepts, techniques, models, validation procedures, uncertainties and limitations of the Finite-Element Method when used for determining the spatial-peak specific absorption rate (SAR) in standardized anatomical models exposed to wireless communication devices, including vehicle-mounted antennas and personal wireless devices, such as hand-held mobile phones. Guidance on modeling such devices and benchmark data for simulation is provided; model contents, meshing and test positions of the anatomical models are defined. This document does not recommend specific SAR values since these are found in other documents, e.g., IEEE C95.1-2005 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz.)

This International Standard specifies protocols and test procedures for the reproducible and conservative measurement of the power density (PD) assuming incident to the head or the body by radio-frequency (RF) transmitting devices, with a defined uncertainty. The protocols and procedures apply for a significant majority of people including children during the use of hand-held and body-worn wireless communication devices. These devices may feature single or multiple transmitters or antennas, and may be operated with their radiating part(s) at distances up to 200 mm from a human head or body . This standard can be employed to evaluate PD compliance of different types of wireless communication devices used next to the ear, in front of the face, mounted on the body, combined with other RF-transmitting or non-transmitting devices or accessories (e.g. belt-clip), or embedded in garments. The overall applicable frequency range is from 6 GHz to 300 GHz.

This International Standard specifies computational procedures using Finite-Difference Time-Domain (FDTD) and Finite Element Methods (FEM) to assess the peak and spatial-averaged power density relevant to the human exposure of the human head or body from devices operating between 6 GHz and 300 GHz. It applies to devices with radiating structures at distances up to and including 200 mm. This includes but is not limited to mobile phones, tablets, and wearables. This standard provides a conservative estimate of the power density of the exposure of the head or body for a significant majority of persons during normal use of these devices.

The scope of this standard is to define the methodology for the application of the finite difference time domain (FDTD) technique when used for determining the peak spatial-average specific absorption rate (SAR) in the human body exposed to wireless communication devices with known uncertainty. It defines methods to validate the numerical model of the device under test (DUT) and to assess its uncertainty when used in SAR simulations. Moreover, it defines procedures to determine the peak spatial average SAR in a cubical volume and to validate the correct implementation of the FDTD simulation software. This document will not recommend specific SAR limits since these are found elsewhere, e.g., in the guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) or in IEEE C95.1.

This part of IEC/IEEE 62704 establishes the concepts, techniques, validation procedures, uncertainties and limitations of the finite difference time domain technique (FDTD) when used for determining the peak spatial-average and whole-body average specific absorption rate (SAR) in a standardized human anatomical model exposed to the electromagnetic field emitted by vehicle mounted antennas in the frequency range from 30 MHz to 1 GHz, which covers typical high power mobile radio products and applications. This document specifies and provides the test vehicle, human body models and the general benchmark data for those models. It defines antenna locations, operating configurations, exposure conditions, and positions that are typical of persons exposed to the fields generated by vehicle mounted antennas. The extended frequency range up to 6 GHz will be considered in future revisions of this document. This document does not recommend specific peak spatial-average and whole-body average SAR limits since these are found in other documents, e.g. IEEE C95.1-2005, ICNIRP (1998).