How to use RF Energy Harvesting for Wireless Charging

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RF Energy HarvestingAmbient Energy sources

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RF Energy HarvestingAmbient RF Energy sources

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RF Energy HarvestingThe Concept

Base station

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TxRx

RF Energy HarvestingThe Harvesting Unit

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Single source

Static receiver

Portable receiver

Multiple sources

Static receiver

Portable receiver

RF Energy HarvestingThe Harvesting Unit

impedance matching

RectifierRF2DC

Summation &

StorageApplication

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RF Energy HarvestingThe Harvesting Antenna

Narrow band antenna

wide band antenna

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Antenna directivity

RF Energy HarvestingThe Harvester IM networkFrequency and power consideration

(-dBm) 0 dBm (+dBm)0

10

20

30

40

50

60

70

80

90

100

Passive ActiveE)%(

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RF Energy HarvestingThe Harvester RF2DC unit

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RF Energy HarvestingThe Harvester storage & summation unit

Single VS. multiple sources

CRF2DC 1

CRF2DC 2

CRF2DC n

+Cstorage

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Cstep upCRF2DC

RF Energy HarvestingConclusions

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advantage:

• Free energy• Wireless energy transfer• Portable devices

Disadvantage:

• Low power density (environment) • Low efficiency (RF2RF) • High efficiency conversion - complicated system• Limitation of ISM band