Findlay R P, Dimbylow P J
Health Protection Agency, Chilton, Didcot, Oxon, UK.
Phys Med Biol. 2008 May 7;53(9):2277-89. doi: 10.1088/0031-9155/53/9/005. Epub 2008 Apr 9.
If an electromagnetic field is incident normally onto a perfectly conducting ground plane, the field is reflected back into the domain. This produces a standing wave above the ground plane. If a person is present within the domain, absorption of the field in the body may cause problems regarding compliance with electromagnetic guidelines. To investigate this, the whole-body averaged specific energy absorption rate (SAR), localised SAR and ankle currents in the voxel model NORMAN have been calculated for a variety of these exposures under grounded conditions. The results were normalised to the spatially averaged field, a technique used to determine a mean value for comparison with guidelines when the field varies along the height of the body. Additionally, the external field values required to produce basic restrictions for whole-body averaged SAR have been calculated. It was found that in all configurations studied, the ICNIRP reference levels and IEEE MPEs provided a conservative estimate of these restrictions.
如果一个电磁场垂直入射到一个理想导电接地平面上，该场会被反射回该区域。这会在接地平面上方产生驻波。如果有人处于该区域内，人体对场的吸收可能会导致在符合电磁准则方面出现问题。为了对此进行研究，已针对接地条件下的各种此类暴露情况，计算了体素模型NORMAN中的全身平均比吸收率（SAR）、局部SAR和脚踝电流。结果被归一化为空间平均场，当场沿身体高度变化时，该技术用于确定一个平均值以与准则进行比较。此外，还计算了产生全身平均SAR基本限制所需的外部场值。结果发现，在所有研究的配置中，国际非电离辐射防护委员会（ICNIRP）的参考水平和美国电气和电子工程师协会（IEEE）的最大允许暴露值（MPE）对这些限制提供了保守估计。
