Welcome to Masayoshi Tanaka  Website  

Research activities of wireless & satellite communications in the following laboratories.
-  College of Industrial Technology, Nihon University, 
     Department of Electrical and Electronic
     Engineering.​
-  NTT Electrical Communications Laboratories.
  

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(1) Engineering test satellite "Sakura"（CS）: Performance evaluation of CS On-board Communication Equipment

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       CS-1: launched in Dec. 1977.

 

Ref:

• Masayoshi Tanaka, Akio Iso, T.Yoshikawa, M.Iguchi, H.Wakana, and K. Kosaka, Characteristics of CS On-board Communication Equipment and the Satellite Link, IEEE AES VOL. AES-22, NO. 3, pp246-254, May, 1986  (Ref pdf)

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(2) Engineering test satellite ETS-IV (Kiku 3）: Irradiation experiment of solid-state power amplifier (SSPA) in space 

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ETS-IV: launched in Feb. 1981.

 

The C-band high power amplifier (HPA) of the CS-1 and -2 transponders employed traveling wave tube amplifiers (TWTAs).

 

We had been developing solid-state high power amplifiers (SSPA) in order to improve HPA reliability.

As part of its efforts, NTT took part in the Japanese national ETS-IV satellite program in developing on-board equipment for the C-band GaAs-SSPA reliability test in space.

 

We successfully carried out the evaluation and verification of a newly developed GaAs SSPA in actual space.

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(3) Commercial communication satellite CS-2:Development of communication payload

 

     CS-2 a: launched in Feb. 1983.

     CS-2 b: launched in Aug. 1983.

NTT (Nippon Telegraph and Telephone Corporation) started satellite communications services for remote islands and emergency use in 1983 with the CS-2 communication satellites which used C-band (6/4 GHz) and Ka-band (30/30 GHz) transponders.

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(4) Commercial communication satellite CS-3: Development of communication payload

 

      CS-3a: launched in Feb. 1988.

      CS-3b: launched in Sept. 1988.

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The CS-3 satellite replaced CS-2 in 1988 at the end of the CS-2 design life. 

 

The CS-3 transponder was composed of two 6/4 GHz bands and ten 30/20 GHz bands transponders.

A single-conversion transponder was introduced instead of the double-conversion transponder employed in the CS-2 to reduce size and weight.

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• A 30 GHz band low noise amplifier, a 30/20 GHz band down-converter, and a 20 GHz band limiter amplifier were newly developed by using GaAs FETs and GaAs diodes to realize a 30/20 GHz band lightweight MIC receiver. 

• The 20 GHz band TWTA provided a 10 W output power and utilized an impregnated cathode to insure long cathode life. Also, dual-collector and velocity tapering techniques were introduced to improve DC-to RF power efficiency.

• The 4 GHz band 7 W output power GaAs FET power amplifiers (SSPAs) were developed to replace TWTs to ensure long life.

     

These new technologies contributed significantly to reducing the CS-3 transponder weight and size and ensuring long life.

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 Ref:

• Masayoshi Tanaka, K Horikawa, H. Mizuno, and K. Okada, "Performance Evaluation of CS-3 Transponder", 15th International Symposium on Space Technology and Science (15th ISTS), pp1035-1041, 1986. Ref. pdf

• Masayoshi Tanaka, Makoto Nakamura, Teruki Okamoto, and Hiroyuki Kumazawa, 30/20 GHz and 6/4 GHz Transponder Development for Communications Satellite CS-3, ICC, 16.5.1-16.5.6, pp507-512, 1986.  (Ref pdf)

•  Masayoshi Tanaka, Hideki Mizuno, and Yutaka Nagai, 30/20 GHz band transponder performance for Japanese Communications Satellite CS-3, 14th International Symposium on Space Technology and Science (14th ISTS), pp787-792, 1984.  (Ref pdf)

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(5) Experimental technology satellite　ETS-VI (Kiku 6）:　Development of Multibeam Communication Payload

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    ETS-VI: launched in Aug. 1994.

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Multibeam satellite communications systems are effective for increasing the signal power flux density at earth stations by narrowing the beamwidth with a large onboard antenna. The increased signal power flux density increases transmission capacity and makes it possible to use small and economical earth stations.

 

NTT had been studying various technologies to achieve a multi-beam satellite communications system. As part of its efforts, NTT took part in the Japanese national ETS-VI satellite program in developing onboard equipment for Ka-band (30/20 GHz) fixed and S-band (2.6/2.5 GHz) mobile multi-beam satellite communication systems and carried out the evaluation and verification of newly developed technologies in actual space.

 

The on-board system was designed to handle SS (Satellite-Switched)-TDMA communications and dynamically-channel-assigned mobile communications.  It included a large-scale satellite switch (IF-SW), and a highly flexible and efficient high power mobile communications transponder employing a Multi-Port Amplifier (MPA), and features compact, lightweight, and highly efficient transponder technologies.

 

The multiport amplifier that we developed for the first time in the world was installed and operated on the ETS-VI satellite in 1994.

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Ref:

    Overview:

• ​Shuichi Samejima, Masayoshi Tanaka and Isao Ohtomo, Overview of satellite on-board multibeam communications system for ETS-VI, Acta Astronautica Vol.28, pp293-300, 1992.  (Ref pdf) 

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    Payload design:​

• Masayoshi Tanaka, Kazuichi Yamamoto, & Kohji Horikawa, Ka-band and S-band Transponder Technologies for Satellite Onboard Multibeam Communications System, Asia-Pacific Microwave Conference (APMC'92), pp261-264, 1992.  (Ref pdf)

• Masayoshi Tanaka, Makoto Nakamura, Makoto Kawai, and Isao Ohtomo, Experimental Fixed and Mobile Multibeam Satellite Communications System, IEEE International Conference on Communications (ICC), ICC'89, pp1587-1594, 52.4.1-52.4.8, 1989. (Ref pdf)

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   Multi-port amplifier (MPA): Ref

•  K.Yamamoto, Masayoshi Tanaka, "High output port isolation and low intermodulation distortion multi-port-amplifier", 22nd European Microwave Conference (EMC), pp1137-11422, 1992. (Ref pdf) 

• K.Horikawa, Masayoshi Tanaka, & Kazuichi Yamamoto, A Highly Flexible and Highly Efficient 100 W S-band Transponder for Multibeam Mobile Satellite Communications, 14th AIAA, AIAA-92-1823, pp148-154, 1992, March 1992.  Ref.   (Ref pdf)

•  K.Horikawa, Masayoshi Tanaka, "S-band Linearized Solid State High Power Amplifier for ETS-6",17th ISTS, pp1773-1778,1990. (Ref pdf) 

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   SS (Satellite-Switched)-TDMA switch (IF-SW):

• Katsuhiko Araki, Masayoshi Tanaka, ETS-VI On-Board Dynamic Switches for Multi-beam Satellite Communications, 20th European Microwave Conference, pp293-298,1990.  (Ref pdf)

• Katsuhiko Araki, Masayoshi Tanaka, Haruhiko Kato, Onboard Large-scale Monolithic IC Switch Matrix for Multibeam Communications Satellites, Acta Astronautica, Vol. 19, NO. 1, pp41-45, 1989.  (Ref pdf)

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(6) Development of communication payloads for commercial satellites, N-STAR-a and b 

 

    N-STAR a: launched in Aug. 1995    N-STAR b: launched in Feb. 1996

 

The N-STAR was one of the world’s largest and most advanced communications satellites and had been used as a successor of CS-3.

 

It carried five payloads in four frequency bands and provides new services such as a flexible unified communication system with different frequency bands, an S-band mobile communication, and a Ka-band high-speed transmission service using its new capabilities. 

 

Various novel technologies, such as inter-channel connectivity among the shaped beam payloads, a mobile multibeam communication system employing a Multi-Port Amplifier (MPA), and a Ka-band multi-beam system with an on-board IF switch (IF-SW), were developed to realize the new capabilities, based on the experience of ETS-VI multibeam payload development.

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Ref:​

    Overview:

• Tadashi Mukai, Masayoshi Tanaka, and Kazuo Nakagawa, Our New Star: N-STAR, NTT Review, pp22-28, Vol.8, No.5, 1996.  (Ref pdf

    Payload design:

• Masayoshi Tanaka and Kyzuichi Yamamoto, New Technologies in N-STAR Communication Payload, 17th American Institute of Aeronautics and Astronautics (AIAA) International Communication Satellite Systems Conference (17th ICSSC), AIAA-98-1248, pp190-200, 1998.  (Ref pdf)

    Multi-Port Amplifier (MPA):

• M.Tanaka, K.Yamamoto, S.Egami, K.Ohkubo, S-band multiple-beam transmitter for N-STAR, AIAA (16th ICSSC), no.96-1159-CP, pp.80-85, Washington DC., USA, Feb. 1996. Ref.

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(7) Reliability assurance method effective for economical satellite on-board equipment 

We proposed a new reliability assurance method of implementing generally used parts (GUPs) in terrestrial.

 

To assure high reliability, specially tailored expensive parts (STPs) have been normally implemented in satellite onboard equipment.
 

In recent years, however, the reliability of GUPs has become as high as that of STPs. Furthermore, GUPs are generally inexpensive because of mass production.
 

The procedure of the new method is the following. First, the failure rates of GUPs used in terrestrial radio equipment are investigated. Secondly, specifically selected GUPs whose structure was not qualified previously, are subjected to several qualification tests, such as shock, vibration, and radiation. Finally, the transponder-level bum-in test is carried out in order to confirm there are no latent defects in the parts.
 

NTT took part in Japan’s ETS program by developing fixed and mobile multibeam communications onboard equipment. This new method was applied to this equipment. Many GUPs, up to about 70% of all parts, were implemented.  A transponder-level burn-in test was carried out for over 3500 hours. No failure parts were found.
 

The method presented here will reduce the cost of satellite onboard equipment and promote satellite communications.

 

Ref :

• Hiroshi Sakamoto, Masayoshi Tanaka, Implementation of Generally Used Parts for Satellite Onboard Equipment, 18th ISTS, 1992. (Ref pdf)  

• Hiroshi Sakamoto, Masayoshi Tanaka, New reliability assurance method effective for economical satellite onboard equipment, 43rd IAF, IAF-92-0420, 1992.  (Ref pdf)