Josaphat Tetuko Sri Sumantyo 1 ， Koichi Ito 2, and Masaharu Takahashi 2 1 Center for Environmental Remote Sensing, Chiba University 2 Graduate School of

Josaphat Tetuko Sri Sumantyo 1 ， Koichi Ito 2, and Masaharu Takahashi 2

1 Center for Environmental Remote Sensing, Chiba University2 Graduate School of Science and Technology, Chiba University

1-33, Yayoi, Inage, Chiba 263-8522 JapanPhone 043-290-3934, Fax 043-290-3933 Email [email protected]

* http://www.jaxa.jp

*) ETS-VIII

Dual Band Circularly Polarized Equilateral Triangular-Patch Array Antenna

for Mobile Satellite Communications

Dual Band Circularly Polarized Equilateral Triangular-Patch Array Antenna

for Mobile Satellite Communications

Josaphat Tetuko Sri Sumantyo 1 ， Koichi Ito 2, and Masaharu Takahashi 2

1 Center for Environmental Remote Sensing, Chiba University2 Graduate School of Science and Technology, Chiba University

1-33, Yayoi, Inage, Chiba 263-8522 JapanPhone 043-290-3934, Fax 043-290-3933 Email [email protected]

Outline of Engineering Test Satellite – VIII (ETS-VIII)

Launch : 2006 by H-IIA Launcher

Design Life Satellite Bus : 10 years

Mission : 3 years

Location : 146 ﾟ E

Weight : Approx. 3,000kg (Initial in Orbit)

Electric Power : 7,500W

Main Characteristics : Large-scale Deployable Reflector, Antenna Feeder, Transponder, Onboard Processor, High Accuracy Clock, Feeder Link Equipment

* http://www.jaxa.jp

External view of ETS-VIII*Geostationary satellite

Applications of ETS-VIII

http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html

El = 48o Geostationary satellite

Necessity to have the beam formedin the direction of low elevation anglefor Mobile Satellite Communications

Engineering Test Satellite-VIII (ETS-VIII)• Launch in 2006• Orbital experiments on Mobile Satellite Communications• Various missions (data communication, mobile satellite broadcasting etc.)

Background

*http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html

ETS-VIII*

Direction of the satellite seen from the center of Tokyo

SPECIFICATIONS

Transmission (Tx) 2655.5 to 2658.0 MHz Frequency bands Reception (Rx) 2500.5 to 2503.0 MHz

Polarisation Left-Handed Circular Polarisation (LHCP)

for both transmission and reception

TARGETS

Elevation angle (El) 48o (Tokyo)

Azimuth angle (Az) 0o to 360o

Minimum gain 5 dBic (a few hundreds kbps)

Maximum axial ratio 3 dB

Isolation 20 dB

Specifications and Targets of ETS-VIII

ETS-VIII *


• Transmission and reception of multimedia information

• Simple satellite-tracking patch array antenna

• Small, thin, compact and light (mounted on bullet train, ship and car roof)

• Low cost

• Maintenance free 　

ETS-VIII*

Simple antenna for ETS-VIII applicationsObjective

* http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html

0.8 cm

Previous type of developed patch array antenna (1)

Publications: J. Tetuko S.S., K. Ito, D. Delaune, T. Tanaka, T. Onishi, and H. Yoshimura, “Numerical analysis of ground plane size effects on patch array antenna characteristics for mobile satellite communications,” International Journal of Numerical Modelling, Vol. 18, No. 2, pp. 95-106, March /April 2005

Patents pending : Japan patent No. 2003-014301 and International patent No. PCT/JP03/05162

Top view

Bird’s eye view

Side view


Patents pending : Japan patent No. 2003-014301, International patent No. PCT/JP03/05162


Publications: D. Delaune, J. Tetuko S.S., K. Ito, and M. Takahashi, “Circularly polarized rounded-off triangular microstrip line array antenna,” Journal of The Communications Society IEICE (in press)

Patents pending : Japan patent No. 2006-023701

a

b

0.8 mm

single feed type dual feed type

LHCP

b/a=0.98

Easy

Stable

Circularly polarised triangular patch

a

bLHCP

b/a=1.00

Circularly polarised triangular patch

h1

h2

a

b

/4patch

microstripline0 804020 60

(unit : mm)

plastic screws

Antenna model Fabricated antenna

J. Tetuko S.S. and K. Ito, "Circularly polarised equilateral triangular patch antenna for mobile satellite communications," IEE Proc. Microwaves, Antennas & Propagation (in press)

Developed antenna : dual band patch array antenna

Reception (Rx)a=b=52.2 mmc=10 mm

Transmission (Tx)a=b=49.1 mmc=10 mm

Substratesh1=0.8mmh2=0.8mm

r=2.17tan =0.00085 w=2.6 mm

Tx1

Tx2

Tx3

Rx1

Rx2 Rx3

patch microstriplineground

x

y

a

wb

/4

(top view)

Az

x

zEl

c

h1h2

J. Tetuko S.S., K. Ito, and M. Takahashi, "Dual band circularly polarized equilateral triangular patch array antenna for mobile satellite communications," IEEE Transaction on Antennas and Propagation, Vol. 53, No. 11, pp. 3477 - 3485, November 2005

Azz

x

y

off

beam directionAz =0°

Rx2

Rx3

Rx1

beam directionAz = 120°

off

Rx2

Rx3

Rx1

beam directionAz = 240° off

Rx2

Rx3

Tx1

Rx1

: patch ‘on’

: patch ‘off’

In the case of LHCP， the main beam will be generated -90o from patch ‘off’

Tx1

Tx1

Tx2

Tx3

Tx2

Tx3Tx2

Tx3

portSwitching mechanism

too easy !

Fabricated antenna

Top view Side view

Bird eye’s view

J. Tetuko S.S., K. Ito, and M. Takahashi, "Dual band circularly polarized equilateral triangular patch array antenna for mobile satellite communications," IEEE Transaction on Antennas and Propagation, Vol. 53, Issue 11, pp. 3477 - 3485, November 2005

Conical-cut plane measurementElevation-cut measurement

Simulation : Zeland IE3D (Method of Moment)

Measurement : Anechoic chamber, Graduate School of Science and Technology, Chiba University

Simulation and measurement

2.40 2.45 2.50 2.55 2.60 2.65 2.70 2.75-50

-40

-30

-20

-10

0

S11 (Rx1)

f - frequency [GHz]

S pa

ram

eter

[dB

]

simulation measurement

S11 (Tx1)

S21 (Rx1-Tx3)

S21 (Rx1-Tx1)

reception

transmission

S-parameter

Frequency characteristics : axial ratio

2.40 2.45 2.50 2.55 2.60 2.65 2.70 2.750

2

4

6

8

10 simulation measurement

f - frequency [GHz]

Ar

- axi

al ra

tio [d

B]

Rx Tx

El=48o

Az=240o Az=300o

reception transmission

0 90 180 270 3600

2

4

6

8

10

0

2

4

6

8

10

#1

Az - azimuth angle [deg]

G -

gain

[dB

ic]

Ar

- axi

al ra

tio [d

B]

#2 #3 #1

#1 #2 #3 #1

simulation

gain

axial ratio

f=2.4900 GHz

3.4 dB5.4 dBic

Simulation　Method of Moment　 Finite substrate

Reception : gain – axial ratio (conical-cut plane)

0 90 180 270 3600

2

4

6

8

10

0

2

4

6

8

10

#1


G -

gain

[dB

ic]

Ar

- axi

al ra

tio [d

B]

#2 #3 #1

#1 #2 #3 #1

measurement

gain

axial ratio

f=2.5025 GHz

5.4 dBic (5 dBic)3.4 dB (3.0 dB)

38o 58o

Reception : gain – axial ratio (elevation-cut)

-90 -60 -30 0 30 60 900

2

4

6

8

10

0

2

4

6

8

10G

- ga

in [d

Bic

]

El - elevation angle [deg]

Ar

- axi

al ra

tio [d

B]


9060 60 3030 00Az=60oAz=240o

gain

axial ratio

Simulation 　Method of Moment　 Finite substrate

Transmission : gain – axial ratio (conical-cut plane)

0 90 180 270 3600

2

4

6

8

10

0

2

4

6

8

10


G -

gain

[dB

ic]

Ar

- axi

al ra

tio [d

B]

simulation

#1 #2 #3

#1 #2 #3

gain

axial ratio

f=2.6400 GHz

5.9 dBic

1.7 dB

0 90 180 270 3600

2

4

6

8

10

0

2

4

6

8

10


G -

gain

[dB

ic]

Ar

- axi

al ra

tio [d

B]

measurement

#1 #2 #3

#1 #2 #3

gain

axial ratio

f=2.6575 GHz

5.8 dBic (5.0 dBic)

2.8 dB (3.0 dB)

38o 58o

Transmission : gain – axial ratio (elevation-cut)

-90 -60 -30 0 30 60 900

2

4

6

8

10

0

2

4

6

8

10G

- ga

in [d

Bic

]

El - elevation angle [deg]

Ar

- axi

al ra

tio [d

B]


9060 60 3030 00Az=120o

Az=300o

gain

axialratio

Developed antenna

Pseudo satellite

Experiment

Outdoor experiment using pseudo satellite under joint research with National Institute of Information and Communications Technology - NICT (November 2004)

Outdoor experiment

Outdoor experiment

38○

，48○

,58○

Graduate School of Science and Technology

experiment car

pseudo satellite

30.m

48○

y

z

Elx y

z

Elx

antenna

measurement calculation

Az=0

Az=270

Az=180

Az=90


Az=0

Az=270

Az=180

Az=90


Az=0

Az=270

Az=180

Az=90

El=38o

El=48o

El=58o

Relative received power [dBm]

(f=2.5025 GHz)

Outdoor experiment : Relative received power (conical-cut plane)

Dual-band triangular-patch array antenna 　 - Both Rx and Tx could be switched very well　　

Problems - Isolation and axial ratio - Spurious radiation from the microstrip-line feed

Summary

Parameters Reception (Rx) Transmission (Tx)

Measurement Simulation Measurement Simulation

Gain (> 5.0 dBic) 5.4 5.4 5.8 5.9

Axial ratio (< 3.0 dB) 3.4 3.4 2.8 1.7

Measurement Simulation

Isolation (< -20 dB) -15.0 -17.0

Main considerations :

- Easy and stable to switch & dual band

- Good gain and axial ratio Thin & light, small and easy to manufacture (p

roximity feeding)

Improvements in this research

Future worksOutdoor experiment using ETS-VIII

El = 48o Geostationary satelliteETS-VIII*

Direction of the satellite seen from the center of Tokyo


Applications

Disaster monitoring

Railway network

Airplane network

Education contents

Logistic delivery

Ferry service

Entertainment contents

help me !

Thank you.

*http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index_j.html

ETS-VIII*

Conical-beam antenna

・ Omnidirectional coverage・ Easy fabrication・ Low gain

A simple antenna for mobile satellite communications that has a beam-tracking antenna with a high gain is developed

Beam-tracking antenna

・ Beam turned in the desired direction・ Necessity of switching devices・ High gain

Antenna types

* http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html

ETS-VIII*

Outdoor experiment : map

Faculty of Law

IMIT

Graduate School of Science and Technology

Pseudo satellite

Faculty of Engineering

RadioisotopeCenter

Analysis Center

0m 40mexperiment area

Transmission-Tx

MODEM (288 kbps)

U/CSSPA

D/CLNA

Spectrum analyzer

Local

Data TransmissionAnalyzer

2.5025 GHz

BPF

BPF

GPS

140 MHz

2.6575 GHz

140 MHz

3-element patch array antenna for each reception and transmission

DAT

Distance pulse

Reception-Rx

Outdoor experiment : Measurement system

UnitSatellite

transmissionMeasurement values at

elevation angle 48°

Frequency GHz 2.5025 2.5025

Transmission power dBW 16.99 -43.15

Feed loss dB 1.00 17.75

Gain of transmission antenna dBi 41.00 0.16

EIRP transmission dBW 56.99 -60.74

Distance between satellite to experiment car

km 37207.83 0.041

Transmission loss dB 191.872.65

(simulation value)

Polarization loss dB 0.2

Fading margin dB 2.50

G/T measurement valueElevation angle 48o dB/K -19.41 -19.41

C/N0 reception dBHz 71.70 75.50

Outdoor experiment : transmission model

-20

-16

-12

-8

-4

0

4

0 5 10 15 20 25 30 35 40

Distance [m]

Rel

ativ

e R

ecei

ve P

ower

[dB

m]

Measurement Calculation

Outdoor experiment : Variation of receive power with distance

Documents

Josaphat Tetuko Sri Sumantyo 1 ， Koichi Ito 2, and Masaharu Takahashi 2 1 Center for Environmental Remote Sensing, Chiba University 2 Graduate School of