Assessment of Human Exposure Levels Due to Mobile Phone Antennas in 5G Networks

Abstract

Assessment of Human Exposure Levels Due to Mobile Phone Antennas in 5G Networks Marta Bonato, Laura Dossi, Silvia Gallucci, Martina Benini, Gabriella Tognola, Marta Parazzini. Assessment of Human Exposure Levels Due to Mobile Phone Antennas in 5G Networks. Int J Environ Res Public Health. 2022 Jan 29;19(3):1546. doi: 10.3390/ijerph19031546. (This article belongs to the Special Issue EMF Exposure Assessment in 5G and 6G Emerging Scenarios in Humans and Environment) Abstract The recent deployment of 5G networks is bringing benefits to the population but it is also raising public concern about human RF-EMF exposure levels. This is particularly relevant considering the next 5G mobile devices, which are placed in close proximity to the subjects. Therefore, the aim of the following paper is focused on expanding the knowledge of the exposure levels in 5G exposure scenarios, specifically for mobile applications, using computational methods. The mobile antenna was designed considering the 5G technology innovations (i.e., mm- wave spectrum, beamforming capability, high gain and wide coverage), resulting in a phased-array antenna with eight elements at the working frequency of 27 GHz. To assess the exposure levels, different types of skin models with different grades of details and layers were considered. Furthermore, not only was the presence of a mobile phone user simulated, but also that of a person in their proximity, who could be hit by the main beam of the phased-array antenna. All the simulations were conducted in Sim4Life platform, where the exposure levels were assessed in terms of absorbed power density averaged over 4 cm2 and 1 cm2, following the ICNIRP guidelines. The results highlighted that the use of the homogeneous skin model led to the absorbed power density peaks being greatly underestimated, with respect to those obtained in multilayer skin models. Furthermore, interestingly, we found that the exposure levels obtained for the person passing nearby were slightly higher than those experienced by the mobile phone user himself. Finally, using the allowed input power for real mobile applications, all the values remained below the limits indicated by the ICNIRP guidelines. Conclusions In conclusion, the aim of further expanding the knowledge about 5G mm-wave exposure in mobile applications was achieved. The results confirmed that at these high frequencies it is essential to consider a multilayer model of the skin rather than a simple homogeneous one that could lead to greatly underestimating the exposure levels. Furthermore, the study highlights those efforts should be focused not only on evaluating the exposure levels for the mobile phone users but also for people passing nearby, who could be hit by the main lobe of the mobile antenna pattern. Finally, it is important to underline that the maximum values of Sab obtained in all the conducted simulations, when scaled for a real input power (23 dBm, i.e., 200 mW) respect the basic restrictions indicated in the ICNIRP guidelines to avoid harmful effects. Future work will deal with the investigation of detailed skin tissues to be used in anatomical models, to take into account the real morphology of human subjects, and the study of the impact of the beamforming capability of the mobile antenna on the exposure scenario. Open access paper: mdpi.com

AI evidence extraction

Main findings

Computational simulations at 27 GHz indicated that homogeneous skin models greatly underestimated absorbed power density peaks compared with multilayer skin models. Simulated exposure for a nearby person intersecting the main beam was slightly higher than for the phone user. When scaled to an allowed real input power (23 dBm, 200 mW), maximum absorbed power density values remained below ICNIRP guideline limits.

Outcomes measured

• Absorbed power density (Sab) averaged over 4 cm²
• Absorbed power density (Sab) averaged over 1 cm²
• Comparison of exposure between phone user and nearby person
• Effect of skin model type (homogeneous vs multilayer) on estimated absorbed power density peaks
• Compliance with ICNIRP guideline limits at scaled real input power (23 dBm / 200 mW)

Limitations

• Computational/simulation study (Sim4Life) rather than measurements in humans
• Results depend on the chosen skin model detail (homogeneous vs multilayer)
• Exposure scenario based on a specific phased-array antenna design (8 elements) at 27 GHz
• Future work noted to include more detailed skin tissues/anatomical morphology and beamforming impacts, implying current modeling simplifications

Suggested hubs

• who-icnirp (0.86)
  Exposure metrics and compliance assessed explicitly following ICNIRP guidelines and limits.
• 5g-policy (0.62)
  Study addresses 5G mmWave exposure scenarios and compliance with guideline limits, relevant to 5G exposure discussions.

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    "exposure": {
        "band": "mmWave",
        "source": "mobile phone",
        "frequency_mhz": 27000,
        "sar_wkg": null,
        "duration": null
    },
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    "outcomes": [
        "Absorbed power density (Sab) averaged over 4 cm²",
        "Absorbed power density (Sab) averaged over 1 cm²",
        "Comparison of exposure between phone user and nearby person",
        "Effect of skin model type (homogeneous vs multilayer) on estimated absorbed power density peaks",
        "Compliance with ICNIRP guideline limits at scaled real input power (23 dBm / 200 mW)"
    ],
    "main_findings": "Computational simulations at 27 GHz indicated that homogeneous skin models greatly underestimated absorbed power density peaks compared with multilayer skin models. Simulated exposure for a nearby person intersecting the main beam was slightly higher than for the phone user. When scaled to an allowed real input power (23 dBm, 200 mW), maximum absorbed power density values remained below ICNIRP guideline limits.",
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        "Future work noted to include more detailed skin tissues/anatomical morphology and beamforming impacts, implying current modeling simplifications"
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        "mobile applications"
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