CONFIDENTIAL

RADIATIVE WIRELESS POWER TRANSFERdriven by nanoelectronics innovation

Peter Lemmens – General Manager imec (Taiwan)

CONFIDENTIAL

1. ENERGY HARVESTING

1831 Faraday dynamo WWII Philips dyno torch Modern dyno torch

1880 Curie discovery of

piezoelectricityEnocean wireless switchRPG7 fuse

Movement

Piezoelectricity

1821 Seebeck experiment 1948 USSR oil lamp powered radio

Temperature

1977 Voyager 2 Radioisotope

Thermoelectric Generator

Light

1839 Becquerel experiment 1954 Bell Labs PV Modern PV

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1. ENERGY HARVESTING

Source Available Power Density Typical Harvested Power Density

Ambient Light

Indoor 0.1 mW/cm2 10 W/cm2

Outdoor 100 mW/cm2 10 mW/cm2

Vibration/Motion

Human 0.5 m at 1 Hz

1 m/s2 at 50 Hz 4 W/cm2

Industrial 1 m at 5 Hz

10 m/s2 at 1 kHz 100 W/cm2

Thermal

Human 20 mW/cm2 30 W/cm2

Industrial 100 mW/cm2 1-10 mW/cm2

RF

GSM Base Station 0.3 W/cm2 0.1 W/cm2

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2. WIRELESS POWER TRANSFER (WPT)

(Non-Radiative) Near-Field Power Transfer

1961

General Electric

Inductively charged toothbrush

2007

Kurs et al., Science

Wireless Power Transfer via

Strongly Coupled Magnetic

Resonances

(Radiative) Far-Field Power Transfer

1901

Nikola Tesla

Idea to wirelessly

transfer energy

1931

Westinghouse

Wirelessly powering a

lightbulb at 5m, 15kW

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3. (NON-RADIATIVE) NEAR-FIELD POWER TRANSFER

Vs

Rs

Cs

Ls Lr

Rr

CrRL

Rectification and

power

management

RF sourceTransmit coil Ls

resonated with Cs

Receive coil Lrresonated with Cr

loss

+ High power

+ High efficiency

+ Standard

- Short distance

- Standard

&

Acer, Asus, AT&T, Broadcom, Canon, Deutsche Telekom, Dialog, Fairchild,

Fujitsu, HP, Hitachi, HTC, Intel, Keysight, Lenovo, LG, Microsoft, Motorola,

Nordic, NXP, Omron, Panasonic, P&G, Qualcomm, Renesas, Rohm,

Samsung, Starbucks, Sandisk, Sharp, Sony, ST, TDK, TI, Toshiba, Witricity, and

others

Asus, Blackberry, Broadcom, Dell, Fairchild, Freescale, Hama, Hitachi, HTC,

Huawei, IKEA, Keysight, LG, Microsoft, Motorola, Nokia, NXP, Omron,

Panasonic, Philips, Powercast, Qualcomm, Ricoh, Samsung, Sony, TDK, TI,

Toshiba, Toyota, and others

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4. (RADIATIVE) FAR-FIELD WIRELESS POWER TRANSFER (WPT)

Source unintentional: RF harvesting

< 0.003 W/m2 = 0.3 W/cm2 (GSM900)

Source intentional: Wireless Power Transfer (WPT)

< 0.03 W/m2 = 3 W/cm2 (4W EIRP)

WPT governed by Friis transmission equation

22

2

22

2

44 r

GEIRP

r

GGPP RR

TTR

received power

transmitted power

gain transmit antenna

gain receive antenna wavelength

distance

Effective Isotropic Radiated Power

Subject to (inter)national restrictions

Internationally, so far,

WPT effort has been

concentrated on the

rectenna

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Monitoring temp, humidity and gas

distributions

Cold chain logistics: remote temp monitoring

Remote cell phone

powered food sensors

4. (RADIATIVE) FAR-FIELD WIRELESS POWER TRANSFER (WPT)

CONFIDENTIAL8

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5. STATE-OF-THE-ART IMEC

imec BEST-OF-CLASS

due to

modeling and optimizing

antenna-rectifier-load

combination

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PCB OVERVIEW RECTENNA

10

An increase in circuit efficiency of 18–25% compared to state-of-the-art

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Transmitter: 3W EIRP, 868-915MHz

30µW continuous DC power

up to 5m distance

60mW DC power during 40ms every 2

minutes up to 12m distance

5. STATE-OF-THE-ART IMEC

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5. STATE OF THE ART – POWERCAST & IMEC

www.powercastco.com

Tx: 3W EIRP @ 915 MHz

Imec rectenna with application Powercast rectenna

Powercast available

power vs distance for

shown rectenna Imec available power vs

distance for shown

rectenna

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6. IMEC WIRELESS POWER TRANSFER –ONGOING RESEARCH

Harvester tests

Hardware realized. Tests

with harvester

successfully performed.

Next generation 2.4 GHz.

Efficiency improvement

• Wave shaping/ modulation

• Diode modeling

On-Metal Miniature

Rectenna

Tx Antenna

Topics: multi-beam, Near-

Far field, analysis tools,

etc.

Patent for hybrid

inductive /radiative

system granted.

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7. SUMMARY

• Far-field WPT, obeying ISM EIRP limits has become feasible.

• In practice this means tens of milliwats, during tens of milliseconds, every

one or two minutes, on distances beyond 10m.

• This is possible through a careful co-design of rectifier and antenna.

• We realize far-field RF harvesters that are :

• Smaller

• More power efficient

• Produce higher DC output voltages

• Operate at lower RF input power levels

Compared to any reported academic or commercial device

operating at the same frequency (UHF 900MHz).

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World-leading nanoelectronics

technology provider

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Industry-relevant solutions

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IMEC Headquarters, Belgium

30+ YEARS

GLOBAL EXCELLENCE