Effects of metallic semi-rimmed spectacles on SAR in the head from a 900MHz frontal dipole source (original) (raw)
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Effects of metallic spectacles on SAR when using communications enabled PDAs in front of the face
2008 Loughborough Antennas and Propagation Conference, 2008
This paper presents simulated and measured results of a study examining the effects of metallic spectacles on the Specific Absorption Rate (SAR) inside a modified Specific Anthropomorphic Mannequin (SAM) head when using various RF sources. We consider dipole sources resonating at 900MHz and 1800MHz as well as three communications enabled PDAs operating in the GSM900 band.
Progress In Electromagnetics Research, 2013
The relationship between specific absorption rate (SAR) and antenna gain inside the head due to the metal-frame spectacles was investigated. The radio frequency (RF) energy source considered is the smartphone used in the frontal face. A computer simulation using CST Microwave Studio 2012 was used for the investigation. Two sets of dipole antennas operated at 900 MHz and 1800 MHz for GSM applications, were used as representative radiation sources from a mobile phone. Parametric studies were conducted to determine the optimum length of the metal rod, and the length was used to study the possibility of RF irradiation of the metal spectacles model. Then, the spectacles model was used as an analysis tool to study the interaction between gain and SAR in the head. The radiation pattern was plotted to identify the causes of the interactions. The gain decreased when the energy source was very close to the spectacles and SAR increased enormously.
2010
This paper presents simulated and measured results from a study looking at the Specific Absorption Rates (SAR) inside the head due to metallic rim-less spectacles, when the head is irradiated by a dipole source in front of the face. The study concentrates on the GSM1800, PCS1900 and UMTS 2100MHz frequency bands. Simulations were carried out using the homogeneous Specific Anthropomorphic Model (SAM) phantom and a heterogeneous head model developed from the Visible Human Project. SAR measurements were carried out using a DASY4 with the modified rear-entry Loughborough SAM head. The measurements and both sets of simulations show that the metallic crossbar can increase the peak 1g SAR inside the head by approximately 5 times in the GSM1800 uplink frequency band.
2011 Loughborough Antennas & Propagation Conference, 2011
The investigation on the changes of Specific Absorption Rate (SAR) inside the head due to metallic straight pin with simple braces added is presented in this paper. The finite integration in time domain (FIT) computer simulation technique was used in this investigation. The head is irradiated by dipole sources in front of the Specific Anthropomorphic Mannequin (SAM) face. Parametric studies show that 1 gram SAR at 900MHz is slightly reduced. However at 1800MHz, it decreased if pin lengths were varied longer than dipole and it can increase if pin is shorter or both has the same length.
SAR variations in the face due to semi-rimmed spectacles and polarized sources at GSM900 and GSM1800
2009
This paper presents experimental and simulated results from a study looking at the effects of semi-rimmed spectacles on the specific absorption rates (SAR) inside the head. Measurements were carried out using a modified specific anthropomorphic mannequin (SAM) phantom head incorporated into a DASY4. 1g SAR was recorded for 14 different semi-rimmed spectacles using CW dipole sources at 900MHz and 1800MHz. Simulations have also been conducted using the digitised SAM head and a pair of spectacles.
IET Seminar Digests, 2007
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.
Specific absorption rate (SAR) in the head of Google glasses and Bluetooth user's
2014 IEEE Latin-America Conference on Communications (LATINCOM), 2014
Two popular wireless communication devices are considered in this paper. Firstly, the Bluetooth which is one of the most popular mobile accessories and the Google glasses which are a representation of the new futuristic vision. It is well known that the absorption of electromagnetic waves on the human head for a certain period of time may lead to health problems such as headaches, or even worse, brain cancer. The Specific Absorption Rate (SAR) is simulated for three different head models and compared with the available international recommendations. The first model used is the Specific Anthropomorphic Mannequin (SAM phantom), as well as two realistic models of human head (i.e., a 34 years old adult and a 10 years old child). The simulations were performed using the finite difference time domain (FDTD) method and the frequency used to feed the antennas was 2.45 GHz.
Case Studies in Thermal Engineering, 2020
Wearable metal objects with high electromagnetic reflection characteristics can cause interference with the incident waves during exposure to the electromagnetic (EM) radiation. Therefore, it is of interest to investigate the effect of metal objects capable of increasing the absorption of EM energy and temperature within the tissues when get exposed to EM radiation. A numerical analysis of increase in specific absorption rate (SAR) and temperature distribution in a human head model when metal objects are placed between the head and radiating source is performed. A realistic three-dimensional heterogeneous human head model, metal objects of different shapes and sizes, and spectacles with different lenses are used. A half-wavelength dipole antenna operating at 1800 MHz served as an EM radiation source. Results show that the presence of metal objects in proximity to the head alters SAR and temperature increase within the tissues. In most cases, metal objects redistribute the EM field incident upon them to a smaller region increasing power absorption, thereby increasing SAR and temperature in that region. The power absorption in head layers is found to be sensitive to metal object's size and shape, and distance of the antenna from the objects.
In this paper, the Specific Absorption Rate (SAR) inside the head due to metallic straight pins and spectacles is investigated. The finite integration in time domain technique (FIT) computer simulation using CST Microwave Studio was used in this investigation. Two sets of dipole antennas operated at 900 MHz and 1800 MHz for GSM application were used in the simulation model represent as radiation sources from MCE. In parametric studies the optimum dipole location is selected for all simulations and only varying both of the pin length and its horizontal separation distance between the head. The results compared with the head worn metallic spectacle.