IEEE 1528-2013 pdf download IEEE Recommended Practice for Determining the Peak Spatial-Average Specific Absorption Rate (SAR) in the Human Head from Wireless Communications Devices: Measurement Techniques
Although strictly not a part of the conservative attributes of the SAM phantom, the physical and electricalcharacteristics and operating frequencies of diferent handsets and sources are important regarding generaconservative overestimate conditions (Kuster et al. (B131]). The criterion for the phantom to be unbiasedwith respect to handset design means in part that handset designs that produce lower assessed SAR valuescorrespond to reduced exposure in real-world situations, and vice versa. The peak spatial-average SARvalue varies greatly between diflerent handset designs because the RF current (distribution and magnitudeflowing on the antenna and handset is determined by the design and separation between the phantom andcurrent-carrying device elements and features. Relevant handset design features include shape,size.curvature, clamshell and other case types, antenna type, placement of any RF components, circuit tracesand matching circuits, and antenna loading by phantom features. More discussion is given in I.4.1.5.
The collective impact of the above parameters is to produce a margin such that the SAR values assessedusing the test procedures of this standard are expected to be higher than during actual use conditions of ahandset. SAR overestimation can never be established for all possible head, device, and positioningconfigurations. In order that the results are not overly conservative. and thereby unnecessarily inhibit theadvancement of new wireless communications technologies, SAR overestimates should be as small aspossible. Achieving an optimal compromise between overestimated or underestiated conditions is acomplex task, which is why the conductivity of the tissue-equivalent liquid is selected to provide therequired overestimaion. Further discussion is included in 1.4.1.5 and Clause 5 on how the homogeneousSAM phantom was derived to overestimate peak spatial-average SAR. Validation of the SAM model byICES TC34 members and other groups is described in 1.4.1.5.
Several homogeneous phantom shapes were previously considered by IEEE Standards CoordinatingCommittee (SCC) 34 (now ICES TC34) before selecting SAM for IEEE Std 1528-2003, including thefollowing:
Existing anthropomorphic phantoms
Rectangular flat phantom
Spherical phantomNew design of anthropomorphic phantom
A closest-spacing condition is best provided by a flat phantom. However, compared with a real head, theflat phantom model may cause considerable changes in antenna loading and impedance due to impropelantenna spacing to the head. Spherical phantoms of appropriate diameter better resemble the proper antennaspacing in the head posterior region. However, the coupling of energy into the phantom and the loading ofhe mobile phone antenna is best represented by an anthropomorphic shape. Therefore, IEEE SCC34 (nowICES TC34) decided to use a “human-likeor anthropomorphic shape. Due to the diversity of existingphantom shapes, volumes, and shell thicknesses. the decision was made to develop a new design of ananthropomorphic phantom. All design details and dimensions are contained in a publicly availablecomputer-aided design (CAD) file” to allow uniform reproduction and manufacture by multiple vendors