A study of the effects of metallic pins on SAR using a specific anthropomorphic mannequin (SAM) head phantom

Abstract

This paper presents the effects of facial metallic pins on the Specific Absorption Rate (SAR) in the head, when radiated by a microwave source placed in front of the face. A Specific Anthropomorphic Mannequin (SAM) is adapted for use with a DASY4 and a digitised SAM head is modelled using inhouse Finite-Difference Time-Domain (FDTD) code, enabling comparisons between measurements and simulations. A continuous wave (CW) half-wave dipole is placed in front of the face, representing a communications enabled personal data assistant mobile communications equipment (PDAMCE). Parametric studies have shown that metallic pins that are roughly half a wavelength long placed along the eyebrow, increase the 1g and 10g SARs at 900MHz by around five fold. A greater than five fold increase is seen at 1800MHz. Measurements show very good agreement with simulations.

Effects of metallic semi-rimmed spectacles on SAR in the head from a 900MHz frontal dipole source

“…Further simulations and measurements have highlighted the sensitivity of the 1g SAR to the separation distance between the head and the spectacles. This sensitivity was also observed in the previous study [9] where it was shown that maximum coupling from the resonant metallic pin occurred when placed approximately 0.06Ȝ from the surface. At 900MHz, this corresponds to about 20mm which is unrealistic for a pair of spectacles.…”

“…In the next stage, the optimum conditions for maximum SAR increase inside the head were sought by simplifying the spectacles to a straight pin and carrying out an analytical study [9]. It was found through simulations that pins ~0.45Ȝ long positioned ~0.06Ȝ away from the surface of the SAM phantom (located horizontally in front of the eyebrows) increased the 1g SAR by more than five times.…”

The SAR effects of popular jewellery on the human head

“…Note, previously the authors found excellent agreement between simulations and measurements with a ring near a flat phantom. Good agreement has also been found with a straight metallic jewellery pin in front of the Loughborough SAM head [31].…”

The Influence of Human Head Model Wearing Metal-Frame Spectacles to the Changes of Sar and Antenna Gain: Simulation of Frontal Face Exposure

“…Concern about possible health effects due to exposures to electromagnetic fields (EMs) has increased among the public and professionals since these communication devices have proliferated around the globe [1][2][3][4][5][6][7][8]. This concern has caused an increase in the research emphasis on analyzing the rate at which electromagnetic radiation is being absorbed by the human body [1][2][3][4][5][6][7][9][10][11][12][13][14][15][16][17].…”

“…Metal objects, such as spectacles, have received limited attention in the literature; however, several studies have been conducted to investigate the maximum SAR for various shapes of spectacles [2,11] and glass lens [2,5]. The paper showed that metallic spectacles can re-distribute the energy produced by the cell phone's antenna, causing the efficiency to drop and the peak SAR to increase.…”