{
    "title": "Metamaterial Power Harvester",
    "inventor_name": "Steven CUMMMER",
    "publication_year": 2013,
    "device_name": "Metamaterial Power Harvester",
    "goal": "Convert ambient electromagnetic wave energy (microwave, Wi-Fi, satellite signals) into usable direct current electricity.",
    "problem_addressed": "Loss of ambient electromagnetic energy and the need for wireless, low-cost power sources for small electronic devices.",
    "concept_summary": "A resonant metamaterial array captures microwave-frequency electromagnetic waves and rectifies them to DC using integrated active electronic components, achieving efficiencies comparable to solar panels.",
    "detailed_description": "The researchers built an array of five fiberglass-copper conductors patterned as metamaterial unit cells on a circuit board. The structure resonantly absorbs incident microwave energy (e.g., 900 MHz) and, through integrated diodes and amplifiers, rectifies the signal to produce a DC output of up to 7.3 V. Laboratory tests reported a peak conversion efficiency of 36.8 % (~=37 %). The design is modular, allowing additional cells to be added for higher power, and can be tuned for other frequencies such as Wi-Fi, satellite, or even acoustic vibrations.",
    "category": "Electromagnetism & Magnetism",
    "principles": [
        "Resonant absorption of electromagnetic waves by metamaterial structures",
        "Rectification of RF signals to DC",
        "Impedance matching to maximize power transfer"
    ],
    "scientific_domains": [
        "Electromagnetics",
        "Materials Science",
        "Electrical Engineering"
    ],
    "mechanisms_of_action": [
        "Resonant capture of microwave energy",
        "Conversion of AC wave energy to DC via rectifier circuit",
        "Use of active electronic components for gain and impedance tuning"
    ],
    "materials": [
        "Fiberglass",
        "Copper",
        "Semiconductor diodes",
        "Operational amplifiers",
        "Transistors"
    ],
    "energy_sources": [
        "Ambient microwave radiation",
        "Wi-Fi signals",
        "Satellite downlink signals"
    ],
    "inputs": [
        "Ambient electromagnetic waves (e.g., 900 MHz microwave, Wi-Fi, satellite)"
    ],
    "outputs": [
        "Direct current electricity (e.g., 7.3 V, up to several tens of milliwatts)"
    ],
    "claimed_performance": "Experimental conversion efficiency up to 36.8 % (~=37 %) and 7.3 V DC output from a 900 MHz source.",
    "experimental_evidence": "Laboratory measurements showed 36.8 % of incident 900 MHz power rectified by the metamaterial array, producing a 7.3 V DC output under test conditions.",
    "replication_status": "Laboratory demonstration; no independent replication reported.",
    "keywords": [
        "Metamaterial",
        "Wireless power harvesting",
        "Rectenna",
        "Microwave energy",
        "Resonant absorber",
        "Ambient RF energy"
    ],
    "related_technologies": [
        "Metamaterial antennas",
        "Rectenna technology",
        "Wireless power transfer"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.6,
    "fringe_score": 0.2,
    "evidence_strength": 0.7,
    "risk_score": 0.1,
    "trl_estimate": 4,
    "source_urls": [
        "http://www.sciencedaily.com/releases/2013/11/131107154818.htm",
        "http://scitation.aip.org/content/aip/journal/apl/103/16/10.1063/1.482447"
    ],
    "organizations": [
        "Duke University Pratt School of Engineering"
    ],
    "applications": [
        "Cell-phone wireless charging",
        "Remote sensor networks",
        "Energy recovery from Wi-Fi or satellite signals"
    ],
    "limitations": [
        "Narrow bandwidth around resonant frequency",
        "Requires line-of-sight or proximity to RF source",
        "Limited power output for high-energy devices"
    ],
    "open_questions": [
        "How to scale the array for higher power levels",
        "Long-term durability of metamaterial structures in real environments",
        "Optimization for multi-frequency harvesting"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "We were aiming for the highest energy efficiency we could achieve... 37 percent.",
        "A maximum of 36.8% of the incident power from a 900 MHz signal is experimentally rectified by an array of metamaterial unit cells.",
        "The device wirelessly converts the microwave signal to direct current voltage capable of recharging a cell phone battery or other small electronic device."
    ]
}