Antenna/Human Body Coupling in 5G Millimeter-Wave Bands: Do Age and Clothing Matter?

Abstract

Antenna/Human Body Coupling in 5G Millimeter-Wave Bands: Do Age and Clothing Matter? G. Sacco, D. Nikolayev, R. Sauleau, M. Zhadobov. Antenna/Human Body Coupling in 5G Millimeter-Wave Bands: Do Age and Clothing Matter? IEEE Journal of Microwaves, doi: 10.1109/JMW.2021.3063256. Abstract With the fast development of 5th generation (5G) mobile networks and prominence of the personal area networks and human-centered communications, people of all ages are increasingly exposed in the upper part of the microwave spectrum. In some exposure scenarios, presence of a textile between the radiating source and skin can affect the power absorption. This study investigates, for the first time, the effect of ageing and impact of textile on the power deposition in a skin-equivalent model under near-field exposure induced by multi-beam radiating structures at 26 GHz and 60 GHz. An array of four Yagi antennas has been used as a representative example of 5G reconfigurable antennas. The maximum increase of the averaged absorbed power density with respect to the averaged value for adults is observed at 70 year (8.8% at 26 GHz and 6.9% at 60 GHz). The strongest decrease is for 5-years-old children (−4.5% at 26 GHz and -3.7% at 60 GHz). In presence of a textile, the absorbed power density can increase or decrease depending on the textile properties (thickness and permittivity) and on the thickness of the air gap between textile and skin. With cotton and wool (considered as representative textile materials) the maximum increase of the averaged absorbed power density is about 40% compared to the bare skin. Excerpts "At microwave frequencies, the difference in exposure levels between children and adults was investigated [3]– [5]. It was demonstrated that, up to 5.6 GHz, the whole-body-average specific absorption rate (SAR) in children can go beyond the exposure limits [6], [7] by 40%–45% whereas remaining below these limits for adults (given the same incident field) [5], [8]. A more recent study [9] investigated the whole-body average SAR using the child models specified by the Commission on Radiological Protection (ICRP) instead of the scaled adult phantoms." "This study deals with the electromagnetic exposure under near-field conditions considering typical reconfigurable antennas at 26 GHz and 60 GHz. For the first time, the analysis is performed taking into account biological tissue permittivity variations with age and presence of a textile in proximity or in contact with skin." ieeexplore.ieee.org

AI evidence extraction

Main findings

In a skin-equivalent model under near-field exposure at 26 GHz and 60 GHz, the maximum increase of averaged absorbed power density relative to adults was reported at age 70 years (8.8% at 26 GHz; 6.9% at 60 GHz), while the strongest decrease was reported for 5-year-old children (-4.5% at 26 GHz; -3.7% at 60 GHz). Presence of a textile could increase or decrease absorbed power density depending on textile thickness/permittivity and air gap; with cotton and wool, the maximum increase was about 40% compared to bare skin.

Outcomes measured

• Averaged absorbed power density in a skin-equivalent model
• Effect of ageing-related tissue permittivity variations on power deposition
• Effect of textile (cotton, wool) properties and air gap on absorbed power density

Limitations

• Study uses a skin-equivalent model (not direct human measurements).
• Results are specific to near-field exposure from a representative four-Yagi antenna array at 26 and 60 GHz.
• Textile effects depend on specific material properties and air-gap conditions (generalizability not established in abstract).

Suggested hubs

• 5g-policy (0.6)
  Study explicitly evaluates exposure-relevant power deposition for 5G mmWave bands (26 and 60 GHz).

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        "frequency_mhz": null,
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        "duration": null
    },
    "population": null,
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    "outcomes": [
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    ],
    "main_findings": "In a skin-equivalent model under near-field exposure at 26 GHz and 60 GHz, the maximum increase of averaged absorbed power density relative to adults was reported at age 70 years (8.8% at 26 GHz; 6.9% at 60 GHz), while the strongest decrease was reported for 5-year-old children (-4.5% at 26 GHz; -3.7% at 60 GHz). Presence of a textile could increase or decrease absorbed power density depending on textile thickness/permittivity and air gap; with cotton and wool, the maximum increase was about 40% compared to bare skin.",
    "effect_direction": "mixed",
    "limitations": [
        "Study uses a skin-equivalent model (not direct human measurements).",
        "Results are specific to near-field exposure from a representative four-Yagi antenna array at 26 and 60 GHz.",
        "Textile effects depend on specific material properties and air-gap conditions (generalizability not established in abstract)."
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "5G",
        "millimeter-wave",
        "26 GHz",
        "60 GHz",
        "near-field exposure",
        "absorbed power density",
        "skin-equivalent model",
        "ageing",
        "children",
        "textile",
        "cotton",
        "wool",
        "antenna-human body coupling",
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    ],
    "suggested_hubs": [
        {
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            "weight": 0.59999999999999997779553950749686919152736663818359375,
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