scope:

The scope of this recommended practice is to specify protocols for the measurement of the peak spatialaverage SAR in a simplified model of the head of users of handheld radio transceivers used for personal wireless communications services and intended to be operated while held next to the ear. It applies to contemporary and future devices with the same operational characteristics as contemporary devices that operate in the 300 MHz-3 GHz frequency range and provides a conservative estimate¹ of the peak spatialaverage SAR representative of that which would be expected to occur in the heads of a significant majority of persons during normal use of these devices, but which may not be the absolute maximum value that could possibly occur under every conceivable combination of head size, head shape, handset orientation, and spacing relative to the head.

This recommended practice does not address the measurement of SAR induced in the external tissues of the head, for example the external ear (pinna). Concepts, measurement techniques, instruments, calibration techniques, phantom models for SAR system validation, and limitations of systems used for measuring the radio frequency (RF) electric field strength for purposes of determining the spatial-peak mass-averaged SAR, e.g., per 1 g or 10 g, in simulated-tissue models, including homogeneous anatomical models of the human head are described. A specific anthropomorphic head model, the dielectric properties and formulations for tissue-equivalent phantom materials, and techniques for verifying the dielectric properties of the phantom material are provided. The relative orientations and spacing between the head model and the handset are defined. Procedures are described for calibrating electric field (E-field) probes used for SAR measurements and evaluating measurement uncertainties associated with probe characteristics, such as isotropy, linearity, spatial resolution, boundary effects, modulation effects, offset voltage, and environmental conditions. Procedures for assessing system uncertainties associated with calibration, probe positioning, and the dielectric properties of the tissue-equivalent solutions are also included. Detailed suggested procedures are provided in the annexes.

Purpose

The purpose of this recommended practice is to provide a protocol for the measurement of the peak spatialaverage SAR in an anatomical model of the human head of users of wireless handsets intended to be operated while held next to the ear. It provides users with standardized and accepted protocols and test procedures, measurement and validation techniques, and means for estimating the overall uncertainty in order to produce valid and repeatable data. Specific SAR limit values are not included because these are given in other documents, e.g., IEEE Std C95.1™-1999.

¹As used in this recommended practice, conservative means that the measured value will not be less than the expected value during normal use by a majority of users-it does not mean that the measured value will not be less than the absolute maximum SAR value that could possibly occur under every conceivable combination head size, head shape, handset orientation, and spacing relative to the head (3.16).