Site: Fujitsu Limited
1-1, Kamikodanaka 4-Chome
Nakahara-ku, Kawasaki 211-88, Japan
http://www.fujitsu.com

Date Visited: June 4, 1997

WTEC: W. Brandon (report author), C. Bostian, A. Mac Rae, S. Townes

Hosts:

BACKGROUND

Fujitsu Limited was established from the Communications Division of Fuji Electric Co., Ltd. in June 1935 and has become a world leader in computers and telecommunications. With about 167,000 employees, Fujitsu owns manufacturing facilities in 34 overseas locations and throughout Japan. Sales of $45 billion in 1996 were approximately 70% computer related, 20% communications and 10% electronic devices. Some current notable products include a VSAT system for multimedia communications, space robots, a mobile satellite news gathering van, microwave components (FETs and HEMTs) and MMICs, and the satellite tracking and control system. Five presentations sampled current research and development related to satellite communications.

RESEARCH AND DEVELOPMENT

Solid State Power Amplifiers

Dr. Shigaki reviewed some products in solid state power amplifiers. A 56 watt, 37.4%, 2.5 GHz amplifier has been developed. A 0.5 watt, 38.0 GHz amplifier for onboard satellite "KIKU VI" was briefly described.GaAs FETS

Fujitsu started its microwave device business in the United States in 1976 and has been a market leader for space applications since 1980.

The Fujitsu FL30 device used by RCA (SATCOM 4) was the first SSPA. This technology changes about every three years for higher power, higher efficiency, etc. It is paradoxical that once a particular device is used and its reliability accepted, it becomes difficult to replace it with an improved product.

The key point is the confirmation of reliability. Some comparative data was given for type "7" and type "2" transistor devices, showing how Fujitsu accomplishes accelerated life tests to confirm reliability.

Table C.1
Comparative Data for Type "7" and Type "2" Transistor Devices

Device Type

"2"

"7"

Gate Metal

Al

WSi/Ti/Au

S/D Metal

AuGe/Ni/Au

AuGe/Ni/Au

Passivation

Silicon Nitride

Silicon Nitride

Lg(u)

0.8

0.6

Failure Mode

Catastrophic

Catastrophic

(Ohmic contact)

(Gate void)



The use of gold was said to have improved life by 500 times. The new failure mode (ohmic contact) has now been made visible after the change to gold. Some comparative data for two versions (6 watt and 7 watt) of the "7" design illustrated the use of accelerated life test at high temperature, with calculated MTTF of 2 x 1010 hours.

Some space qualified devices provide 42 dBm at L-band and 39 dBm at X and Ku-bands, the highest performance on the market. Fujitsu is striving for a 30 watt device. Fujitsu wants to provide samples of pHEMT within one year. Development of a Ka-band MMIC is expected to require 2 years.

High Temperature Superconductors

Mr. Yamanaka discussed research on HTS for use as transmit and receive filters. The HTS filters will provide unloaded Q values of 10 to 100 times that of conventional filters. Resulting performance improvements have the equivalent effect of increasing the effective EIRP.

Materials used are YBCO, YBaCuO (Tcn 90K), BiSrCa CuO Bi2221 phase (Tcn 80-90K) and 2223 phase (Tcn 105K). Thin films are deposited on MgOLaA103 and thick films on MGOLa A103+A1203. Some comparative performance results were shown for X-band filters showing a ten fold reduction in Rs.

Satellite Systems

An overview revealed the rapid introduction of new communications services into Japan. Multi-channel digital TV broadcast and Internet access via satellite will begin within a year. Superbird, JCSAT and BS satellites will provide DirecPC, DirecTV, PerfecTV, and data broadcasting.

Fujitsu was scheduled to begin a high speed 1 to N multicasting data distribution service in July 1997. The value of this service can be seen by comparing delivery times for various modes of delivery in Table C.2.

Table C.2
Delivery Times for Various Modes of Information Delivery

Media/File Size

3.5 in. FPD

CD ROM

 

1.4 Mbytes

640 Mbytes

Fuji Satellite Info.

Delivery System (FSIS)

5.7 sec

44 min

OCN, INS64 (128 kbps)

87 sec

660 min

Telephone (33.6 kbps)

341 sec

2,600 min

Physical Delivery

2 days

2 days



A consumer application is the advertising of 9,000 used cars/week, requiring distribution of a gigabyte to over 3,000 locations, which was not possible with the terrestrial network. The data broadcast service enables this volume of cars to be sold at auction

REFERENCES

Fujitsu Limited. Annual Report. March 1996.


Published: December 1998; WTEC Hyper-Librarian