In-to-out body path loss for wireless radio frequency capsule endoscopy in a human body.

Abstract

Physical-layer characterization is important for design of in-to-out body communication for wireless body area networks (WBANs). This paper numerically investigates the path loss of an in-to-out body radio frequency (RF) wireless link between an endoscopy capsule and a receiver outside the body using a 3D electromagnetic solver. A spiral antenna in the endoscopy capsule is tuned to operate in the Medical Implant Communication Service (MICS) band at 402 MHz, accounting for the properties of the human body. The influence of misalignment, rotation of the capsule, and human body model are investigated. Semi-empirical path loss models for various homogeneous tissues and 3D realistic human body models are provided for manufacturers to evaluate the performance of in-to-out-body WBAN systems.

AI evidence extraction

Main findings

Using a 3D electromagnetic solver, the paper numerically characterizes in-to-out body path loss for a capsule endoscopy RF link with a spiral antenna tuned to the MICS band (402 MHz). It reports that misalignment, capsule rotation, and the human body model/tissue assumptions influence the modeled path loss, and provides semi-empirical path loss models for homogeneous tissues and realistic 3D human body models.

Outcomes measured

• In-to-out body RF path loss
• Effects of capsule/receiver misalignment
• Effects of capsule rotation
• Effects of human body model/tissue type on path loss
• Semi-empirical path loss models for homogeneous tissues and realistic 3D human body models

Limitations

• Numerical/simulation study (3D electromagnetic solver) rather than measurements in humans
• No health outcomes assessed; focus is physical-layer/path loss characterization

Suggested hubs

• medical-implants (0.86)
  Focuses on RF link for a capsule endoscopy device operating in the MICS band.
• rf-exposure-assessment (0.55)
  Provides modeled path loss characterization and semi-empirical models relevant to RF propagation/exposure modeling.

{
    "study_type": "engineering",
    "exposure": {
        "band": "RF",
        "source": "medical implant (capsule endoscopy) / WBAN in-to-out body link",
        "frequency_mhz": 402,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "In-to-out body RF path loss",
        "Effects of capsule/receiver misalignment",
        "Effects of capsule rotation",
        "Effects of human body model/tissue type on path loss",
        "Semi-empirical path loss models for homogeneous tissues and realistic 3D human body models"
    ],
    "main_findings": "Using a 3D electromagnetic solver, the paper numerically characterizes in-to-out body path loss for a capsule endoscopy RF link with a spiral antenna tuned to the MICS band (402 MHz). It reports that misalignment, capsule rotation, and the human body model/tissue assumptions influence the modeled path loss, and provides semi-empirical path loss models for homogeneous tissues and realistic 3D human body models.",
    "effect_direction": "unclear",
    "limitations": [
        "Numerical/simulation study (3D electromagnetic solver) rather than measurements in humans",
        "No health outcomes assessed; focus is physical-layer/path loss characterization"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "wireless body area networks",
        "WBAN",
        "capsule endoscopy",
        "in-to-out body communication",
        "path loss",
        "MICS band",
        "402 MHz",
        "spiral antenna",
        "3D electromagnetic solver",
        "human body model"
    ],
    "suggested_hubs": [
        {
            "slug": "medical-implants",
            "weight": 0.85999999999999998667732370449812151491641998291015625,
            "reason": "Focuses on RF link for a capsule endoscopy device operating in the MICS band."
        },
        {
            "slug": "rf-exposure-assessment",
            "weight": 0.5500000000000000444089209850062616169452667236328125,
            "reason": "Provides modeled path loss characterization and semi-empirical models relevant to RF propagation/exposure modeling."
        }
    ]
}

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