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 *
*http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
• 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
Previous type of developed patch array antenna (2)
Patents pending : Japan patent No. 2003-014301, International patent No. PCT/JP03/05162
Previous type of developed patch array antenna (3)
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
Az - azimuth angle [deg]
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]
simulation measurement
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
Az - azimuth angle [deg]
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
Az - azimuth angle [deg]
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]
simulation measurement
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
measurement calculation
Az=0
Az=270
Az=180
Az=90
measurement calculation
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
*http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
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