Investigation of SAR (Specific Absorption Rate) in Different Head Models Placed in Shielded Space

2019 · Harm · Low evidence

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HarmLow evidencePaper 1606

Study snapshot

Publicationmanual · 2019

Study typeengineering

Reported directionHarm

Evidence ratingLow

Abstract

Investigation of SAR (Specific Absorption Rate) in Different Head Models Placed in Shielded Space Psenakova Z, Benova M, Mydlova J. Investigation of SAR (Specific Absorption Rate) in Different Head Models Placed in Shielded Space. 2019 IEEE 20th International Conference on Computational Problems of Electrical Engineering (CPEE).15-18 Sept. 2019. Abstract This article deals with effects of electromagnetic (EM) fields to different types of numerical models of human head. There are differences between specific absorption rate (SAR) near human head model inside shielded space like in elevator or non-shielded space (open area). In the presented approach, the investigation is focused on modelling of EM field proceeded on the finite integration method. The simulations were carried out for specific scenario where a person/passenger was placed in the shielded space using a cellular phone. The results were evaluated in terms of the SAR values - the determination of EM energy absorption inside the human head. The dipole antenna with a frequency of 900 MHz was designed and working as radio frequency source. In the proposed matching method, two models of human head - SAM homogenous human head model and AustinMan model - were chosen to model three different distances of the cellular phone from the human head surface. Both have the dielectric properties determined to the evaluated frequency of source. The numerical results have shown that the obtained maximal SAR values in shielded/enclosure (such as the elevator) is higher than are maximum values determined according to maximum SAR in European standards limit. Additionally, the obtained SAR values are higher than the results achieved by the open space simulations. Conclusions In this paper, the study of the electromagnetic energy absorption changes caused to the human head models in different situations-open and shielded space was proposed. The near-field exposure results from have shown that the SAR values vary for the antenna distance and space, where is the antenna placed as well as to the use of human head model. The changes of EM fields relate to the above-mentioned process - occurrence of EM fields reflection from the surface of iron shielded space. This reflected wave interferes with the primary wave from the radiation source, resulting in increased wave amplitude. In a shaded environment, this affects the object by absorbing direct waves from the source in the tissue as well as reflected waves, resulting in a higher SAR value. In some cases of our simulation scenarios, the SAR values results are not within the limits for public radio- frequency EM field exposure by ICNIRP. However, it could be caused by setting the specific parameters of our simulations - such as dielectric parameters of materials, number of voxels, boundary conditions in each space and model of human head. On the other hand, the cases presented in this paper, represent a risk for long-term exposure of human body, especially of human head, to EM field. In this article we would like to show differences between open space and shielded space, which could be some vehicles like train, car and another shielded spaces with low signal from base station like underground park places or elevators. Mobile phone has highest power in this types of spaces and places, which was proven in our simulations. [12] ieeexplore.ieee.org

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeengineering

Effect directionharm

PopulationNot supplied

Sample sizeNot supplied

ExposureRF · 900 MHz

Evidence strengthLowConfidence: 74% · Peer reviewed: unknown

Main findings

Finite-integration-method simulations using a 900 MHz dipole source (cell phone scenario) found higher maximal SAR values in a shielded/enclosed space (e.g., elevator) than in open space, with SAR varying by antenna distance and head model (SAM vs AustinMan). The authors report that in some simulated scenarios, SAR results were not within ICNIRP public exposure limits and that maximal SAR in shielded/enclosure could exceed European standards limits; they note this may depend on simulation parameter settings.

Outcomes measured

Specific absorption rate (SAR) in head models
Maximum SAR relative to European standards/ICNIRP public limits
SAR differences in shielded/enclosed vs open space
SAR variation by phone-to-head distance and head model (SAM vs AustinMan)

Limitations

Numerical simulation study (no human measurements).
Authors note results may be influenced by simulation parameter choices (e.g., dielectric parameters, number of voxels, boundary conditions, head model).
SAR values and specific exceedance magnitudes are not provided in the abstract.

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Specific absorption rate (SAR) in head models",
    "Maximum SAR relative to European standards/ICNIRP public limits",
    "SAR differences in shielded/enclosed vs open space",
    "SAR variation by phone-to-head distance and head model (SAM vs AustinMan)"
  ],
  "main_findings": "Finite-integration-method simulations using a 900 MHz dipole source (cell phone scenario) found higher maximal SAR values in a shielded/enclosed space (e.g., elevator) than in open space, with SAR varying by antenna distance and head model (SAM vs AustinMan). The authors report that in some simulated scenarios, SAR results were not within ICNIRP public exposure limits and that maximal SAR in shielded/enclosure could exceed European standards limits; they note this may depend on simulation parameter settings.",
  "effect_direction": "harm",
  "limitations": [
    "Numerical simulation study (no human measurements).",
    "Authors note results may be influenced by simulation parameter choices (e.g., dielectric parameters, number of voxels, boundary conditions, head model).",
    "SAR values and specific exceedance magnitudes are not provided in the abstract."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "unknown",
  "keywords": [
    "SAR",
    "specific absorption rate",
    "900 MHz",
    "mobile phone",
    "shielded space",
    "elevator",
    "enclosure",
    "finite integration method",
    "SAM head model",
    "AustinMan",
    "near-field exposure",
    "ICNIRP"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.72,
      "reason": "Abstract explicitly references ICNIRP public exposure limits and compares simulated SAR to limits."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: Not supplied
PubMed: Not supplied

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