No.22(AUGUST 2003)

Recently, the demand for data communication has been growing rapidly due to the Internet and other factors.
Therefore, we developed several kinds of high performance optical fibers which can satisfy the demands of the next generation transmission systems.
These fibers are a middle dispersion NZDSF (BBG(R)-LA), an ultra low dispersion slope NZDSF (BBG(R)-DF), a low water peak SMF (BBG(R)-SM-WF) and holey fiber (HF) with several holes in cladding region.
We developed these fibers considering them as cabling because of our expertise in the cabling field.

The standardization of 10 Gigabit Ethernet (following 10G Ethernet) has been completed, and we believe Ethernet will be applied more and more in not only LAN (Local Area Network) but also MAN (Metropolitan Area Network) and WAN (Wide Area Network).
But lack of management function in comparison with the usual SONET/SDH is a problem to be solved when Ethernet technique is applied in long haul transmission.
So we developed the 10G Ethernet media converter XGMC-1001, which can be managed precisely from remote site with our new signaling system, IFS (Inter-frame Signaling) function, based on LSS (Link Signaling Sub-layer) that NTT Network Innovation Laboratories developed.
This equipment can transmit data up to 80km, and features remote monitoring functions such as in-band IP communication, loop back test via remote site and power-off detection at remote site by IFS.

We have developed Gigabit Ethernet Multiplexer, GMX-1010L, which transmits 10 channels of Gigabit Ethernet over long distances using a single pair of optical fibers by multiplexing technique: It provides large capacity long distance data transmission between data centers of common carriers at a low cost.
This equipment enables long distance multiplexed transmission up to 120km over a pair of DSF fibers at the full wire rate for 10 channels of Gigabit Ethernet, using our original packet multiplexing system based on 10 Gigabit Ethernet.
It can provide a reliable management system, since it has many remote monitoring functions: SNMP (Simple Network Management Protocol) agent, Telnet, link status relay function (to notify quickly of link failure on any channel to remote GMX-1010L), loop-back test function (to judge whether the path is good or not), and performance monitor function for supervising transmission quality.

With the spread of radio communication networks including the cellular phone,now conspicuous are big antennas for various base stations installed on steel towers in the suburbs and on the roofs of buildings and the tops of electric poles in cities. From now on, small and high gain antennas are anticipated,from the scenic point of view and for the environment.
And now a triplet antenna of quasi-millimeter wave band integrated on a circuit board for FWA systems has been developed.
A gain beyond 29.3dBi has been realized using the size of 200mm x 200mm x 13mm in a wide frequency range of 25GHz through 27GHz,which is the 26GHz band. This antenna is usable for FWA communications in both P-P systems and P-MP systems connected to the broadband Internet networks. This product has been delivered to Toshiba Corp.

We report results for evaluation experimentally, using the developed antenna where the influence of window glass (indoors) and snow-stuck/ water (outdoors) on the surface of the antenna are thought to be the biggest problems of radio wave propagation.
In this case we presumed that the developed quasi-millimeter wave band small high gain triplet antenna for the FWA service systems, with integrated circuit board type, will be installed both indoors and outdoors.

We have developed the triple-band internal antenna for Clamshell type mobile phone.
The frequency range was suitable for European Mobile Phone system: 900MHz and 1800MHz, and USA Mobile Phone system: 1900MHz.
To develop the triple band antenna, we increased the bandwidth at 1800MHz ~ 1900MHz.
We concentrated on optimizing the relation between internal antenna and print circuit board, and found the best antenna position and design.
Also we determined the influence of varying the LCD panel position on Clamshell type mobile phone.

Low-loss Highly-foamed Polyethylene Coaxial Cable (LHPX) is used in feeders for base stations for cellular phones. The operating frequencies of cellular phones are getting higher and higher into the range of 2.0 to 2.2 GHz.
To meet that range, we have investigated low-loss highly-foamed dielectric materials from the viewpoint of blowing agents, nucleating agents, and base polymers, and have developed LHPX with an attenuation rate about 10% lower than conventional cables at 2.2 GHz.

Data traffic and signal transmission speed in electronic equipment increase every year, and a transmission line of 10Gbps or more is needed in electronic circuit board in the near future.
The design of circuit pattern becomes difficult for transmission speed, so another type of board or part of the electric transmission line substituted for optical line have been researched.
We selected the wave guide inserted O/E (Opt-Electronic) Circuit Board structure, which used the UV hardening epoxy based resin, and can improve design possibility.
Low transmission loss was obtained, though optical wave guide and mirror were made directly on the glass epoxy circuit board. Moreover, the influence of PWB(Printed Wiring Board)process and reflow test was so small that structural validity was shown.

Recently the multi layered high density flexible circuit board has been adopted as electric circuit board for devices such as cellular phones. The flexible circuit board has advantages in the view point of reduced thickness and light weight compared with the conventional multi layer rigid circuit board.
TAB tape technology, which can fabricate a fine pitch pattern, was adopted to these purposes and 3 layer TAB tape was developed.
The main feature of the TAB tape process is continuous tape production system, which is called RtoR (Reel to Reel) manufacturing method. Though the process enables fine pitch pattern to be fabricated,conventional lamination press is not applicable because of the continuous tape production system. So the above TAB tape process is said to be unsuitable for multi layering circuit board.
We used roll lamination technology, instead of press technology, and tape type RCC(Resin Coated Copper) was adopted for the process. Multi layering structure was realized with these processes, and the structure, process, characteristics were studied.

We have established the manufacturing technique for 0.016-mm-diameter super fine Cu-In-Sn alloy (NN alloy*) wire suitable for the ultra micro coaxial cable used for probe cables, and developed the 46 AWG-sized micro coaxial cable which employs this alloy wire. The ultra micro coaxial cable has excellent electrical and mechanical properties. The probe cables, which is composed of a number of ultra micro coaxial cables, is reiable and can be used for ultrasonic diagnostic instruments. The 46 AWG-sized ultra micro coaxial cable has a diameter half that of conventional probe cables which have 196 cores of 40 AWG-sized micro coaxial cables, and we expect it to be applied to endoscopic ultrasonography cables.

Electric discharge machining (EDM) is an important technology for precision manufacturing of such items as metal molds for IC lead frames and electronic parts.
Wire electric discharge machining demands high-speed cutting and high-precision machining to realize productivity and improved accuracy of metal molds.
We considered two types of coated wire electrodes: Both consist of a thin copper zinc alloy layer and core material, one being a copper zinc alloy coated with a brass layer while the other is a Cu-Sn-In alloy with high heat resistance and high electrical conductivity.
We studied the use of a coating layer with a high concentration of zinc and then developed the HIR electrode for high-speed and accurate cutting, and the HIS electrode for super-high-speed cutting.

L-COP (Low Expansion Copper) is a copper-based composite formed by the dispersion of Cu2O in matrix Cu.
The composite exhibits a blending of properties of Cu, with its high thermal conductivity, and Cu2O, with its low thermal expansion.
The properties can be changed at will by controlling the volume fraction of Cu2O quite adequately described by the composite rule-of-mixtures (ROM) behavior.
L-COP can be used in those fields where an excellent combination of high thermal and electrical conductivity and low thermal expansion are required, such as in heat sinks for semiconductor devices.
The purpose of our work is to study the manufacture of L-COP by Cold Isostatic Pressing (CIP) and subsequent hot extrusion, with the aim of producing a composite with high thermal conductivity and low thermal expansion.
The composite produced a coefficient of thermal expansion improved by 10% or more, and with heat conductivity better by 20% or more, when compared with L-COP manufactured in conventional powder metallurgy processing.

Electric power is one of most important lifelines in our society, and electric equipment needs periodic maintenance and inspection for a stable supply of electric power.
Since overheat phenomenon is a common abnormal state of electric equipment, we developed the overheat detection system "CAN-NETSU-KUN" using an odor detector and capsules.
Our new system can detect abnormal high temperature of electric devices such as electric terminal, joint in switchboard and cubicle-type substation. The system is composed of an odor detector and odor capsules.
There are 3 types of odor capsules for the temperaturs, 80,100 and 120 deg. C.
The capsules are sealed with solder of low temperature fused metal and contain an odor liquid.
The capsules are attached to electrical equipment at several points of its surface with an odor detector.
If the electrical equipment is heated over a specified temperature, the temperature of the attached capsule rises, too.
Then the low temperature fused metallic solder of the capsule melts and the odor liquid is vaporized.
After a few minutes the odor detector senses the vaporized gas and emits alarms.
The system ensures constant safe conditions for various types of electrical equipment and their many surface points at a lower cost than conventional methods, such as thermo couple, thermo-stat and etc.