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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. *) ETS-VIII.
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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 *) ETS-VIII Josaphat Tetuko Sri Sumantyo 1,Koichi Ito 2, and Masaharu Takahashi 2 1 Center for Environmental Remote Sensing, Chiba University 2 Graduate School of Science and Technology, Chiba University 1-33, Yayoi, Inage, Chiba 263-8522 Japan Phone 043-290-3934, Fax 043-290-3933 Email jtetukoss@faculty.chiba-u.jp Josaphat Tetuko Sri Sumantyo 1,Koichi Ito 2, and Masaharu Takahashi 2 1 Center for Environmental Remote Sensing, Chiba University 2 Graduate School of Science and Technology, Chiba University 1-33, Yayoi, Inage, Chiba 263-8522 Japan Phone 043-290-3934, Fax 043-290-3933 Email jtetukoss@faculty.chiba-u.jp * http://www.jaxa.jp
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 External view of ETS-VIII* Geostationary satellite * http://www.jaxa.jp
Applications of ETS-VIII http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
Background • Engineering Test Satellite-VIII (ETS-VIII) • Launch in 2006 • Orbital experiments on Mobile Satellite Communications • Various missions (data communication, mobile satellite broadcasting etc.) Necessity to have the beam formed in the direction of low elevation angle for Mobile Satellite Communications ETS-VIII* El = 48o Geostationary satellite Direction of the satellite seen from the center of Tokyo *http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
Specifications and Targets of ETS-VIII ETS-VIII * *http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
Objective Simple antenna for ETS-VIII applications • 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* * 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
Previous type of developed patch array antenna (2) Bird’s eye view Top view Side view 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
b LHCP b/a=1.00 a Circularly polarised triangular patch b Easy LHCP Stable b/a=0.98 0.8 mm a dual feed type single feed type
b a patch l/4 h2 h1 plastic screws microstripline (unit : mm) 0 20 40 60 80 Circularly polarised triangular patch 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)
Reception (Rx) a=b=52.2 mm c=10 mm Transmission (Tx) a=b=49.1 mm c=10 mm Substrates h1=0.8mm h2=0.8mm er=2.17 tan d=0.00085 w=2.6 mm Developed antenna : dual band patch array antenna (top view) Rx1 y Tx3 Tx1 Az x c Rx2 Rx3 b Tx2 w a microstripline patch l/4 h2 z ground h1 El x 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
y z Az x too easy ! Switching mechanism port off off Tx1 Rx2 Rx2 Tx1 Tx2 Rx1 Rx1 Tx2 Tx3 Rx3 Rx3 Tx3 beam direction Az= 120° beam direction Az=0° Rx2 Tx1 : patch ‘on’ Rx1 Tx2 : patch ‘off’ beam direction Az= 240° Rx3 Tx3 off In the case of LHCP,the main beam will be generated-90ofrom patch ‘off’
Fabricated antenna Bird eye’s view Side view Top 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
Simulation and measurement Simulation :Zeland IE3D (Method of Moment)Measurement :Anechoic chamber, Graduate School of Science and Technology, Chiba University Elevation-cut measurement Conical-cut plane measurement
S-parameter transmission reception
Frequency characteristics : axial ratio El=48o Az=300o Az=240o reception transmission
Reception : gain – axial ratio (conical-cut plane) Simulation • Method of Moment • Finite substrate 5.4 dBic 3.4 dB 5.4 dBic (5 dBic) 3.4 dB (3.0 dB)
Transmission : gain – axial ratio (conical-cut plane) Simulation • Method of Moment • Finite substrate 5.9 dBic 1.7 dB 5.8 dBic (5.0 dBic) 2.8 dB (3.0 dB)
Outdoor experiment Pseudo satellite Experiment Developed antenna Outdoor experiment using pseudo satellite under joint research with National Institute of Information and Communications Technology - NICT (November 2004)
Outdoor experiment pseudo satellite 48 ○ antenna 30.m 38 48 ,58 ○ ○ ○ , z z El El experiment car Graduate School of Science and Technology y y x x
Outdoor experiment : Relative received power (conical-cut plane) Relative received power [dBm] (f=2.5025 GHz) El=38o El=58o El=48o
Summary • 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
Improvements in this research • Main considerations : - Easy and stable to switch & dual band - Good gain and axial ratio • Thin & light, small and easy to manufacture (proximity feeding) Future works Outdoor experiment using ETS-VIII ETS-VIII* El = 48o Geostationary satellite Direction of the satellite seen from the center of Tokyo *http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
Applications help me ! Disaster monitoring Airplane network Entertainment contents Logistic delivery Education contents Ferry service Railway network
ETS-VIII* Thank you. *http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index_j.html
Antenna types ETS-VIII* Beam-tracking antenna Conical-beam antenna ・Omnidirectional coverage ・Easy fabrication ・Low gain ・Beam turned in the desired direction ・Necessity of switching devices ・High gain A simple antenna for mobile satellite communications that has a beam-tracking antenna with a high gain is developed * http://www.jaxa.jp/missions/projects/sat/tsushin/ets8/index.html
Outdoor experiment : map IMIT Analysis Center Faculty of Law Graduate School of Science and Technology Pseudo satellite Radio isotope Center experiment area 0m 40m Faculty of Engineering
Outdoor experiment : Measurement system 3-element patch array antenna for each reception and transmission Transmission-Tx Reception-Rx GPS 2.5025 GHz 2.6575 GHz Local MODEM (288 kbps) 140 MHz SSPA BPF U/C 140 MHz LNA BPF D/C Data Transmission Analyzer Spectrum analyzer Distance pulse DAT
Outdoor experiment : Variation of receive power with distance