Yoshiyuki FUJINO National Institute of Information and Communications Technology, Japan Wireless Power Transmission Activity in NICT

Yoshiyuki FUJINONational Institute of Information and Communications Technology, Japan

Wireless Power Transmission Activity in NICT

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RRL Technical Report (1982.12)Stratosphere Radio Relay System (1989-1997)

Rectennas for small airplane experimentRectennas for Airship experiment

Random Rectenna Array (2006)R&D of ETS-8 (2006-2009)

S-band Active Phased Array Beam direction changes of large-scale antenna

on ETS-8 at the satellite orbit

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RRL Technical Report (1982.12)Based on NASA/DoE ProjectSSPS Study in RRL (now NICT) Mainly electromagnetic environmental

point of view.Upper atmosphere effect for high RF powerGround EMC assessment by SSPS, etc

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5

Stratosphere Radio Relay System (1989-1997) Rectenna for small airplane experiment (MILAX,

1992) Rectenna for Airship experiment (ETHER, 1995)

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MILAX demonstration (1992.8) MIcrowave Lifted Airplane

eXperiment. 350m, 40 sec flight is succeeded 29th, Aug.,1992.

Tx power １ｋＷRx power ８８ＷHeight １５ｍRectenna efficiency 52%

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A Rectenna Array for ETHER (1995) For Energy Transmission toward High altitude

airship ExpeRiment Antenna : Circular Microstrip Antenna Polarization : Dual polarization Frequency : 2.45GHz Subarray Panel

Size : 34.1cm×42.7cm Number of elements : 20 Nominal input power flux density : 850 W/m2

Efficiency : 81% Rectenna array for ETHER

Size : 2.7m×3.4m Confirmed maximum power 2.8kW

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9

Random Rectenna Array - Harmonics re-radation from a rectenna -

Harmonics are generated by the diode which is a nonlinear device included in the rectenna.

Normally, such harmonics are removed by the filter, but rest of the components are re-radiated to the space.

EMC Problems for existing communication system

Rectenna and re-radiation of harmonics

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Concept of a Random Rectenna Rrray (RRA) 　

In-Phase rectenna array

φ φ φ φ

Averaged Directivity

Normally, in the rectenna array, due to the phase of the re-radiated harmonics, strong directivity is observed in specific direction.

So, re-radiated phase can be controlled randomly.

Random Rectenna Arrayφ1 φ2 φ3 φn

Random Rectenna Array

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Outer view of 25-elements 2-D Random rectenna array

Antenna Rectifying circuit

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-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90-15

-10

-5

0

5

10

15

20

25

30

35

-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90-15

-10

-5

0

5

10

15

20

25

30

35

Angle[deg] Angle[deg]e.i.r.

p.[dB

m]

e.i.r.

p.[dB

m]

Inphase Random

測定値評価値

Measurement result (2) 25 elements 2-D RRA

Sidelobes at ±45° Averaged beam

Error with measurement value ・・・ Valiations of amplitude and phase error of rectenna array

Validity of random rectenna array is confirmed

Theory

10.0dB suppression

Experiment6.0dB

suppression

Exp. Theory

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S-band Active Phased Array large-scale reflector antenna pattern

measurement of ETS-8

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16

Reflector (Transmitting)

Reflector (Receiving)

@JAXA

18 m

Transmitting array feed

S band antennaused for receiving

antenna

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S band Active Phased Array Use self diplexing antenna Thin (less than12cm),Light weight (less than 17kg) Analog voltage control phase shifter (No bit error) Use antenna module Sum and Diff. pattern tracking is available

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Outer view of ETS-8 Large Deployable Reflector

37ｍ

Feed Tx Unit

Feed Rx Unit

17ｍ

37ｍ

17ｍ

Two Tennis courts

テニスコート：24m×11m

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Beam is moved to left hand side (west side) ！

　　 Received level variation

Akashi→increase

Kita-kyusyu 　→ decrease

Yamagawa 　 → decrease

・

Ｋｉｔａ - ｋｙｕｓ y ｕ

・

Ｙａｍａｇａｗａ

・

Ａｋａｓｈｉ・

EastWest

Kyusyu beam and earth station

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20Daily variation of receiving level of kyusyu beam

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21LDR antenna pattern measurement

(1) Verification of daily variation of receiving level(2) Experiment of correcting beam position error

Beam shift cased by thermal distortion of reflector

Receiving level is changed by beam shift.

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22

Eclipse

Example of level variation around eclipse in spring

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Temp sensor data 　

大型展開アンテナの温度センサー

-160

-110

-60

-10

40

11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30 16:00 16:30 17:00 17:30 18:00TIME (UT)

TEM

P (

℃)

LDR TX REF M10 TEMPLDR TX REF M5 TEMPLDR TX REF M12 TEMP

食時間帯

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Beam shift at the Eclipse

-1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4

Azimuth (deg)

5.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

Ele

v at i

on

(de

g)

5.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

-1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.45.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

-1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.45.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

-1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.45.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

-1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.45.4

5.5

5.6

5.7

5.8

5.9

6

6.1

6.2

Before ecripse22 ：20

After ecripse①22 ：50

After ecripse②23 ： 10

After ecripse③23 ： 30

Variation of Beam direction

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LDRA pattern measurement Conclusion

(1)Pattern measurement results of LDRA was shown.

(2)Daily variation of receiving level at earth station casedby beam shift.

(3)Thermal distortion of reflector causes the beam shift.

Space base large scale antenna is also important in SSPS technology, so this will be variable data for such system.

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SummaryWe Introduced Wireless Power Transmission

Activity in NICT. It has two lineup.

One is for Rectenna array development for Microwave Power Transmission.

The other is Space Communication technology that can be applicable to WPT.

Both lineup is introduced.

Documents

Yoshiyuki FUJINO National Institute of Information and Communications Technology, Japan Wireless Power Transmission Activity in NICT