The Numerical Assessment of RF Human Exposure to Microwave Ovens with Contact-Type Doors

PAPER manual Electronics 2025 Engineering / measurement Effect: mixed Evidence: Low

Read original paper → DOI: 10.3390/electronics14050873 Evidence Lab

Abstract

The Numerical Assessment of RF Human Exposure to Microwave Ovens with Contact-Type Doors Tian R, Wei J-C, Lu M. The Numerical Assessment of RF Human Exposure to Microwave Ovens with Contact-Type Doors. Electronics. 2025; 14(5):873. doi.org Abstract In complex electromagnetic environments, cardiac pacemakers may be interfered with easily. Microwave ovens, as common household appliances, may display electromagnetic leakage, which may pose risks to pacemaker wearers. This work evaluates the electromagnetic exposure of pacemaker wearers under various conditions. One involves different distances from the microwave oven to the human body, and the other involves a distinct oven door gap. This work uses COMSOL Multiphysics to establish a human thoracic cavity model with a heart and unipolar pacemaker, as well as a model of a microwave oven with contact-type doors. The results show that the specific absorption rate (SAR10g) and temperature increase in the thoracic cavity and heart tissue are inversely proportional to the distance from the microwave source. They are directly proportional to the oven door gap size. The induced electric field intensity, the temperature increase, and the induced voltage in the pacemaker show the same trend. When the human body is closest to the microwave oven with the largest door gap (D = 100 mm, d = 0.3 mm), the SAR10g and temperature increase of the thoracic cavity and heart tissue reach their maximum values, which are significantly below the safety standards recommended by ICNIRP. Similarly, the maximum value of the temperature increase and the induced electric field intensity in the pacemaker are below the safety standard recommended by ISO 14708-3 (+2 °C) and IEC 60601-1-2 (28 V/m). The maximum induced voltage at the pacemaker electrode is 5.322 mV, which exceeds the sensing sensitivity setting recommended by ISO 14117 (2 mV) for unipolar pacemakers. These findings demonstrate that microwave ovens with contact-type doors electromagnetic radiation do not threaten human health under normal usage conditions. However, the maximum value of the induced voltage exceeds the sensing sensitivity of some unipolar pacemakers, which may affect the operation of the unipolar pacemaker. This phenomenon requires attention from clinicians and patients. We still recommend that pacemaker wearers keep a distance from microwave ovens when using them. Conclusions Through the simulation of the induced electric field intensity, the SAR10g distribution, the temperature increase after 30 min of exposure of the human thoracic cavity, the heart tissue, and the cardiac pacemaker, and the induced voltage at the electrode under different distances and oven door gap sizes, the following conclusions were drawn: • Human thoracic tissue: The SAR10g and temperature increase in the thoracic cavity gradually decreased as the distance between the human thoracic cavity and the microwave source increased, and they increased with the size of the oven door gap. Under a condition of a 100 mm distance from the microwave source and a 0.3 mm oven door gap, the SAR10g and temperature increase in the thoracic cavity reached their maximum values, which were 0.295 W/kg and 0.008687 °C, respectively. Nevertheless, the SAR10g value and temperature increase remained below the safety standard recommended by ICNIRP. • Heart tissue: The SAR10g value and temperature increase in the heart tissue were lower than those of the thoracic tissue, and the change trends in the heart tissue were similar to those in the thoracic tissue. Under the most unfavorable conditions (distance of 100 mm and a 0.3 mm oven door gap), the maximum SAR10g value and temperature increase in the heart tissue were 0.000789 W/kg and 0.00001156 °C, respectively, which were far below the safety standard recommended by ICNIRP. Although the SAR10g of the human thoracic cavity and heart tissue for a single exposure was below the safety standard recommended by ICNIRP, long-term exposure could have led to electromagnetic energy accumulation in the tissue, potentially causing health risks [31]. • Electromagnetic compatibility of cardiac pacemaker: The temperature increase, the induced electric field intensity, and the induced voltage of the cardiac pacemaker were also inversely proportional to the distance between the human thoracic cavity and the microwave source, and directly proportional to the size of the microwave oven door gap. The induced electric field intensity, temperature increase, and induced voltage of the cardiac pacemaker reached their highest values when the distance was 100 mm and the oven door gap was 0.3 mm, which were 27.7 V/m, 0.000892 °C and 5.322 mV, respectively. However, the induced electric field intensity and temperature increase remained below the immunity recommended by IEC 60601-1-2 (28 V/m) and the temperature rise standard recommended by the ISO 14708-3 standard (+2 °C). ISO 14117 recommends setting the sensing sensitivity of the unipolar pacemaker to 2 mV. Some manufacturers set the sensing sensitivity according to the characteristics of their products at the factory. For example, Medtronic’s unipolar pacemaker is set to 2.8 mV [32], and Biotronik’s unipolar pacemaker is set to 2.5 mV [33]. The maximum induced voltage used in this work was 5.322 mV. This value already exceeded the sensitivity of the aforementioned pacemakers. We hope that this conclusion is helpful to those involved in research. To sum up, under the conditions set in this work, the electromagnetic radiation of the microwave oven with contact-type doors had a minimal impact on the human body, remaining within the safe range. However, when the human body is within 300 mm of the microwave oven, it may affect the operation of the unipolar pacemaker. It was recommended that patients implanted with medical devices, especially those with pacemakers, maintain a safe distance or replace aging microwave ovens, while also minimizing the time spent near an operating microwave. In addition, patients are advised to opt for bipolar pacemakers whenever possible to reduce potential electromagnetic exposure risks. Open access paper: mdpi.com

AI evidence extraction

At a glance

Study type

Engineering / measurement

Effect direction

mixed

Population

Simulated human thoracic cavity model with heart and unipolar pacemaker (pacemaker wearers)

Sample size

—

Exposure

microwave microwave oven · 30 min (simulated temperature increase after 30 min exposure)

Evidence strength

Low

Confidence: 78% · Peer-reviewed: yes

Main findings

COMSOL simulations found SAR10g and temperature rise in thoracic cavity and heart tissue decreased with increasing distance from the microwave oven and increased with larger oven door gaps. Under the most unfavorable modeled condition (distance 100 mm, door gap 0.3 mm), maximum SAR10g and temperature increases in thoracic cavity (0.295 W/kg; 0.008687 °C) and heart tissue (0.000789 W/kg; 0.00001156 °C) were reported as below ICNIRP limits; pacemaker induced E-field (27.7 V/m) and temperature rise (0.000892 °C) were below IEC 60601-1-2 and ISO 14708-3 thresholds, but induced electrode voltage (5.322 mV) exceeded the ISO 14117 sensing sensitivity setting (2 mV) for unipolar pacemakers.

Outcomes measured

SAR10g (thoracic cavity, heart tissue)
Temperature increase (thoracic cavity, heart tissue, pacemaker)
Induced electric field intensity (pacemaker)
Induced voltage at pacemaker electrode
Distance-to-source effects
Oven door gap size effects
Comparison to ICNIRP/ISO/IEC standards

Limitations

Numerical/simulation study (COMSOL) rather than measurements in humans
Frequency of microwave source not stated in the abstract
Results depend on modeled distances and door gap sizes; real-world variability not described
Statement about potential long-term energy accumulation is speculative within the abstract

Suggested hubs

who-icnirp (0.6)
Compares modeled SAR/temperature outcomes to ICNIRP safety standards.

View raw extracted JSON

{
    "study_type": "engineering",
    "exposure": {
        "band": "microwave",
        "source": "microwave oven",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "30 min (simulated temperature increase after 30 min exposure)"
    },
    "population": "Simulated human thoracic cavity model with heart and unipolar pacemaker (pacemaker wearers)",
    "sample_size": null,
    "outcomes": [
        "SAR10g (thoracic cavity, heart tissue)",
        "Temperature increase (thoracic cavity, heart tissue, pacemaker)",
        "Induced electric field intensity (pacemaker)",
        "Induced voltage at pacemaker electrode",
        "Distance-to-source effects",
        "Oven door gap size effects",
        "Comparison to ICNIRP/ISO/IEC standards"
    ],
    "main_findings": "COMSOL simulations found SAR10g and temperature rise in thoracic cavity and heart tissue decreased with increasing distance from the microwave oven and increased with larger oven door gaps. Under the most unfavorable modeled condition (distance 100 mm, door gap 0.3 mm), maximum SAR10g and temperature increases in thoracic cavity (0.295 W/kg; 0.008687 °C) and heart tissue (0.000789 W/kg; 0.00001156 °C) were reported as below ICNIRP limits; pacemaker induced E-field (27.7 V/m) and temperature rise (0.000892 °C) were below IEC 60601-1-2 and ISO 14708-3 thresholds, but induced electrode voltage (5.322 mV) exceeded the ISO 14117 sensing sensitivity setting (2 mV) for unipolar pacemakers.",
    "effect_direction": "mixed",
    "limitations": [
        "Numerical/simulation study (COMSOL) rather than measurements in humans",
        "Frequency of microwave source not stated in the abstract",
        "Results depend on modeled distances and door gap sizes; real-world variability not described",
        "Statement about potential long-term energy accumulation is speculative within the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave oven",
        "electromagnetic leakage",
        "pacemaker",
        "unipolar pacemaker",
        "SAR10g",
        "induced voltage",
        "induced electric field",
        "temperature increase",
        "COMSOL Multiphysics",
        "ICNIRP",
        "IEC 60601-1-2",
        "ISO 14708-3",
        "ISO 14117"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.59999999999999997779553950749686919152736663818359375,
            "reason": "Compares modeled SAR/temperature outcomes to ICNIRP safety standards."
        }
    ]
}

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

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