RF Safe

Exposure of Insects to RF EMF from 2 to 120 GHz

2018 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 2159

Finite-difference time-domain simulations using Micro-CT–derived insect models found absorbed RF power depended on frequency for all studied insects, with a general increase at and above 6 GHz compared with below 6 GHz. The authors report that shifting 10% of…

Study snapshot

Publicationmanual · 2018
Study typeengineering
Reported directionUnclear
Evidence ratingInsufficient

Abstract

Exposure of Insects to RF EMF from 2 to 120 GHz Thielens A, Bell D, Mortimore DB, Greco MK, Martens L, Joseph W. Exposure of Insects to Radio-Frequency Electromagnetic Fields from 2 to 120 GHz. Scientific Reports. 8:3924. Mar 2, 2018. DOI: 10.1038/s41598-018- 22271-3 Abstract Insects are continually exposed to Radio-Frequency (RF) electromagnetic fields at different frequencies. The range of frequencies used for wireless telecommunication systems will increase in the near future from below 6 GHz (2 G, 3 G, 4 G, and WiFi) to frequencies up to 120 GHz (5 G). This paper is the first to report the absorbed RF electromagnetic power in four different types of insects as a function of frequency from 2 GHz to 120 GHz. A set of insect models was obtained using novel Micro-CT (computer tomography) imaging. These models were used for the first time in finite-difference time-domain electromagnetic simulations. All insects showed a dependence of the absorbed power on the frequency. All insects showed a general increase in absorbed RF power at and above 6 GHz, in comparison to the absorbed RF power below 6 GHz. Our simulations showed that a shift of 10% of the incident power density to frequencies above 6 GHz would lead to an increase in absorbed power between 3-370% Excerpt Figure 4 illustrates the frequency dependence of the absorption of RF-EMFs in the Western Honeybee in terms of the ratio of the electric field strength inside the insect to the maximum electric field in the simulation domain. At the currently used frequencies for telecommunication (<6 GHz), the wavelength is relatively large compared to the insects and the waves do not penetrate into the insects, which results in lower Pabs values. At 12-24 GHz, the fields penetrate more and more into the insect as the wavelength becomes comparable to the insects' size and the conductivity increases as well. At the highest studied frequencies, the fields penetrate less deep into the insect, but their amplitude is higher, resulting in a similar or slightly lower P abs . Figure 5 shows the P abs linearly averaged over all twelve plane waves as a function of frequency for all studied insects. The absorbed power increases with increasing frequency from 2-6 GHz for all insects under exposure at a constant incident power density or incident electric field strength of 1 V/m... The three smaller insects show their maximum at a frequency higher than 6 GHz: 60 GHz, 24 GHz, and 12 GHz for the Australian Stingless Bee, the Beetle, and the Honey Bee, respectively.... We investigated the absorbed radio-frequency electromagnetic power in four different real insects as a function of frequency from 2-120 GHz. Micro-CT imaging was used to obtain realistic models of real insects. These models were assigned dielectric parameters obtained from literature and used in finite-difference time-domain simulations. All insects show a dependence of the absorbed power on the frequency with a peak frequency that depends on their size and dielectric properties. The insects show a maximum in absorbed radio frequency power at wavelengths that are comparable to their body size. They show a general increase in absorbed radio- frequency power above 6 GHz (until the frequencies where the wavelengths are comparable to their body size), which indicates that if the used power densities do not decrease, but shift (partly) to higher frequencies, the absorption in the studied insects will increase as well. A shift of 10% of the incident power density to frequencies above 6 GHz would lead to an increase in absorbed power between 3-370%. This could lead to changes in insect behaviour, physiology, and morphology over time due to an increase in body temperatures, from dielectric heating. The studied insects that are smaller than 1 cm show a peak in absorption at frequencies (above 6 GHz), which are currently not often used for telecommunication, but are planned to be used in the next generation of wireless telecommunication systems. At frequencies above the peak frequency (smaller wavelengths) the absorbed power decreases slightly. Open access paper: nature.com

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 directionunclear
PopulationInsects (four types; includes Western honeybee, Australian stingless bee, beetle; one additional insect type not clearly specified in provided text)
Sample size4
ExposureRF
Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Finite-difference time-domain simulations using Micro-CT–derived insect models found absorbed RF power depended on frequency for all studied insects, with a general increase at and above 6 GHz compared with below 6 GHz. The authors report that shifting 10% of incident power density to frequencies above 6 GHz would increase absorbed power by 3–370% (depending on insect).

Outcomes measured

  • Absorbed RF electromagnetic power (Pabs) as a function of frequency (2–120 GHz)
  • Frequency dependence/peak absorption frequency related to insect size
  • Modeled change in absorbed power with a shift of incident power density to >6 GHz

Limitations

  • Simulation study (modeled absorption), not direct measurement of biological/health outcomes
  • Dielectric parameters were taken from literature (details not provided in the excerpt)
  • Incident power density/electric field assumptions may not reflect real-world exposures (not fully specified in provided text)
View raw extracted JSON
{
  "study_type": "engineering",
  "exposure": {
    "band": "RF",
    "source": "wireless telecommunication systems (2G/3G/4G/WiFi; future 5G)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Insects (four types; includes Western honeybee, Australian stingless bee, beetle; one additional insect type not clearly specified in provided text)",
  "sample_size": 4,
  "outcomes": [
    "Absorbed RF electromagnetic power (Pabs) as a function of frequency (2–120 GHz)",
    "Frequency dependence/peak absorption frequency related to insect size",
    "Modeled change in absorbed power with a shift of incident power density to >6 GHz"
  ],
  "main_findings": "Finite-difference time-domain simulations using Micro-CT–derived insect models found absorbed RF power depended on frequency for all studied insects, with a general increase at and above 6 GHz compared with below 6 GHz. The authors report that shifting 10% of incident power density to frequencies above 6 GHz would increase absorbed power by 3–370% (depending on insect).",
  "effect_direction": "unclear",
  "limitations": [
    "Simulation study (modeled absorption), not direct measurement of biological/health outcomes",
    "Dielectric parameters were taken from literature (details not provided in the excerpt)",
    "Incident power density/electric field assumptions may not reflect real-world exposures (not fully specified in provided text)"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "insects",
    "RF EMF",
    "2–120 GHz",
    "mmWave",
    "5G",
    "WiFi",
    "finite-difference time-domain",
    "FDTD",
    "Micro-CT",
    "absorbed power",
    "dielectric heating",
    "power density"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.55,
      "reason": "Discusses planned shift of telecom frequencies to >6 GHz up to 120 GHz (5G) and implications for absorption."
    }
  ]
}
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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: 10.1038/s41598-018
PubMed: Not supplied

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