Reflection Properties of the Human Skin From 40 to 110 GHz: A Confirmation Study

Bioelectromagnetics · 2021 · Unclear · Moderate evidence

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UnclearModerate evidencePaper 1096

Study snapshot

PublicationBioelectromagnetics · 2021

Study typeexposure_assessment

Reported directionUnclear

Evidence ratingModerate

Abstract

Reflection Properties of the Human Skin From 40 to 110 GHz: A Confirmation Study Andreas Christ, Adrian Aeschbacher, Fereshteh Rouholahnejad, Theodoros Samaras, Bernadetta Tarigan, Niels Kuster. Reflection Properties of the Human Skin From 40 to 110 GHz: A Confirmation Study. Bioelectromagnetics. 2021 Jul 21. doi: 10.1002/bem.22362. Abstract Several recent theoretical dosimetric studies above 6 GHz apply generic layered skin models. For this frequency range, new experimental phantoms for over-the-air performance of wireless devices were proposed that simulate the impedance matching effects of the stratum corneum layer (SCL) with a low-loss coating layer. The aim of this study was to verify the skin models by comparing their reflection coefficients S11 with measurements of 37 human volunteers (21 males, 16 females, 5-80 years) at 21 body locations (10 at palm, 11 at arm/face) with different SCL thicknesses, using waveguides covering frequencies from 40 to 110 GHz. Such measurements were also carried out with the phantom material. The statistical analysis showed strong evidence that S11 depends on the SCL thickness and no evidence that S11 depends on sex. The measured S11 values for thin and thick skin can be represented by SCL layers of 15 and 140 μm, respectively. These values correspond well to the assumptions of previous studies. (The cohort did not include volunteers doing heavy manual work.) The phantom material mimics the matching effect of the SCL with deviations from the waveguide measurements of less than 0.85 dB (22%), which confirms the suitability of layered phantoms to represent the electromagnetic reflection/absorption of human skin pubmed.ncbi.nlm.nih.gov

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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 typeexposure_assessment

Effect directionunclear

PopulationHuman volunteers (21 males, 16 females; ages 5–80 years)

Sample size37

ExposuremmWave

Evidence strengthModerateConfidence: 74% · Peer reviewed: yes

Main findings

In measurements of 37 volunteers at 21 body locations using waveguides from 40–110 GHz, statistical analysis showed strong evidence that S11 depends on stratum corneum layer (SCL) thickness and no evidence that S11 depends on sex. Measured S11 for thin vs thick skin could be represented by SCL layers of 15 and 140 μm, and a phantom material mimicked the SCL matching effect with deviations <0.85 dB (22%), supporting suitability of layered phantoms for representing skin reflection/absorption.

Outcomes measured

Skin reflection coefficient (S11) from 40 to 110 GHz
Association of S11 with stratum corneum layer (SCL) thickness
Association of S11 with sex
Agreement between phantom material and human skin measurements (deviation in dB/%)

Limitations

Cohort did not include volunteers doing heavy manual work

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "mmWave",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Human volunteers (21 males, 16 females; ages 5–80 years)",
  "sample_size": 37,
  "outcomes": [
    "Skin reflection coefficient (S11) from 40 to 110 GHz",
    "Association of S11 with stratum corneum layer (SCL) thickness",
    "Association of S11 with sex",
    "Agreement between phantom material and human skin measurements (deviation in dB/%)"
  ],
  "main_findings": "In measurements of 37 volunteers at 21 body locations using waveguides from 40–110 GHz, statistical analysis showed strong evidence that S11 depends on stratum corneum layer (SCL) thickness and no evidence that S11 depends on sex. Measured S11 for thin vs thick skin could be represented by SCL layers of 15 and 140 μm, and a phantom material mimicked the SCL matching effect with deviations <0.85 dB (22%), supporting suitability of layered phantoms for representing skin reflection/absorption.",
  "effect_direction": "unclear",
  "limitations": [
    "Cohort did not include volunteers doing heavy manual work"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "millimeter wave",
    "40–110 GHz",
    "human skin",
    "reflection coefficient",
    "S11",
    "stratum corneum",
    "skin models",
    "phantom material",
    "waveguide measurements",
    "dosimetry"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.55,
      "reason": "Study measures human skin electromagnetic reflection properties in the 40–110 GHz mmWave range relevant to >6 GHz wireless device exposure modeling."
    }
  ]
}

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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: 10.1002/bem.22362
PubMed: 34289515

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