The experiment described in – involved a perfect electric conductor (PEC) reflector positioned between a head model and folded loop antenna driver. The spatial peak SAR needs to be reduced at the design stage of the material because the possibility of a spatial peak SAR exceeding the recommended exposure limit cannot be completely ruled out. These studies showed that the position of the shielding material is an important factor for the effectiveness of SAR reduction. The effects of attaching conductive materials to mobile phones for SAR reduction were reported in ref. This statistical study established that the SAR increased while the radiation efficiency decreased when the resonant frequency of the armature equaled the resonant frequency of the antenna. investigated the antenna efficiency, bandwidth, and SAR as a function of a mobile phone's armature-associated parameters, such as the length, thickness, width, and partition from the phantom. They observed that the homogeneous model overestimated the SAR for a λ/4 antenna above a handset at 835 MHz with a radiation power of 600 mW. studied cellular telephones operating at 8 MHz using a λ/4 and a 3λ/4 monopole antenna. They aimed to understand the effects of the tissue position and the corporal model on the antenna performance. The study by Jensen and Rahmat-Samii considered a monopole, a side mounted Planar-Inverted F Antenna (PIFA), a top mounted curved inverted F-antenna and a back-mounted PIFA that utilized the FDTD method. Note that research effort has also been dedicated to people suffering from headaches, fatigue and a loss of concentration after using their cellular mobile phones. Laboratory tests on cockroaches have shown that radiation from mobile phones can have an adverse effect on overall health –. Mobile phone radiation of the body's cells, brain or immune system has been suggested to elevate the threat of developing diseases, ranging from cancer to Alzheimer's disease. The exposure of the human head to the near-field of a cellular mobile phone can be appraised by measuring the SAR in a human-head phantom or by calculating the exposure using a human-head numerical model. Radio frequency (RF) safety guidelines have been issued to prevent exposure to excessive electromagnetic fields in terms of the SAR.
The specific absorption rate (SAR) is the parameter used to evaluate power absorption in the human head. Because the use of such mobile devices increases every year, an extensive study on the health risk from hazardous electromagnetic fields is currently in progress. Portable communication devices are widely used.
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