The properties of bird feathers as converse piezoelectric transducers and as receptors of microwave radiation. II. Bird feathers as dielectric receptors of microwave radiation.

Abstract

The characteristics of bird feathers as receptors of microwave fields were investigated in the 10- to 16-GHz region. Experiments were conducted coupling the specimen (feather) to a length of waveguide which served, together with other microwave components, as a primary detector. Microwave power radiation patterns were measured both in the presence and in the absence of the specimen. Results indicated a substantial increase in the microwave power collected in the forward direction and a decrease of the radiation pattern beam width when the feather was present. Fruthermore, some experiemental evidence indicated the possibility of inducing piezoelectric effects in the specimen by audiofrequency pulse-modulated microwave fields. These results are important in view of (i) the fundamental role that feathers play in the life of birds and (ii) the influence of environmental factors on bird behaviour.

AI evidence extraction

Main findings

Bird feathers coupled to a waveguide in the 10- to 16-GHz region were associated with a substantial increase in microwave power collected in the forward direction and a decrease in radiation pattern beam width compared with measurements without the feather. The authors also report some experimental evidence suggesting the possibility of inducing piezoelectric effects in the specimen using audiofrequency pulse-modulated microwave fields.

Outcomes measured

• Microwave power radiation patterns with and without feather specimen
• Forward-direction microwave power collected
• Radiation pattern beam width
• Evidence of induced piezoelectric effects from audiofrequency pulse-modulated microwave fields

Limitations

• No sample size reported in abstract
• No quantitative effect sizes or statistical analysis reported in abstract
• Exposure metrics (e.g., incident power density, SAR) not reported in abstract
• Study appears to be a laboratory/engineering setup on feather specimens; relevance to whole animals/behavior not directly tested in abstract

{
    "study_type": "other",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Microwave power radiation patterns with and without feather specimen",
        "Forward-direction microwave power collected",
        "Radiation pattern beam width",
        "Evidence of induced piezoelectric effects from audiofrequency pulse-modulated microwave fields"
    ],
    "main_findings": "Bird feathers coupled to a waveguide in the 10- to 16-GHz region were associated with a substantial increase in microwave power collected in the forward direction and a decrease in radiation pattern beam width compared with measurements without the feather. The authors also report some experimental evidence suggesting the possibility of inducing piezoelectric effects in the specimen using audiofrequency pulse-modulated microwave fields.",
    "effect_direction": "unclear",
    "limitations": [
        "No sample size reported in abstract",
        "No quantitative effect sizes or statistical analysis reported in abstract",
        "Exposure metrics (e.g., incident power density, SAR) not reported in abstract",
        "Study appears to be a laboratory/engineering setup on feather specimens; relevance to whole animals/behavior not directly tested in abstract"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "bird feathers",
        "microwave radiation",
        "dielectric receptor",
        "waveguide",
        "radiation pattern",
        "10-16 GHz",
        "pulse-modulated",
        "piezoelectric effects"
    ],
    "suggested_hubs": []
}

Comments

Log in to comment.

No comments yet.