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R & D Review


No.106 October 2009

Sheet Type Wide Band Dipole Antennas

For the rapidly expanding wireless communication field, we have developed a transparent sheet type wide band dipole antenna that covers a wide frequency range; from digital terrestrial broadcasting to GPS, wireless LAN and ETC/DSRC services to replace the conventional method of using multiple antennas corresponding to the frequencies used. The basic construction is a planar dipole antenna having an oval shape, with a distinctive tapered feeder aimed to achieve VSWR characteristics over a wider bandwidth. By applying appropriate notches and slits to the antenna element, a great improvement in antenna directivity and gain is achieved especially for 5 .8 GHz circular-polarized waves of ETC/DSRC. By fabricating the antenna element with a minute mesh, this antenna, with an essentially omnidirectional radiation pattern, is expected to be developed for use in vehicles, underground shopping centers, housing complexes and also as an antenna for distributing information in the community.
[Key words] Sheet type, Wide band, Dipole Antenna, VSWR, Circulary Polarization, Notch, Slit, Radiation Pattern, Transparent

Development of Laser Guides with Square Core Fibers

Laser processing techniques are popularly used in the photovoltaic and flat panel display industries. The condensed top-hat laser beam shape allows improved processing form and higher speed fabrication. We have developed resin and silica cladding square core fibers and confirmed that their condensed beam patterns were uniform top-hat shape. In addition, we evaluated the mechanical characteristics and laser durability with optical connectors.
[Key words] Square Core, Thin-film Photovoltaics, Top-hat, Condensed Beam

Development of Optical Thin Film for High Power Lasers and its Applications

High-power and high-quality lasers are composed of many optical components, the surfaces of which are coated with optical thin films. The laser-induced damage threshold (LIDT) of the optical thin film is one of the most serious problems in these components. Therefore, optical components coated with highly damage resistant thin films are strongly required. In this paper we report on the dvelopment of a highly damage resistant optical thin film and confirmed the practicability of the film.
The LIDT of an anti-reflection (AR) coating on an optical fiber end face coated by pulsed YAG laser irradiations was 25 .0 J/cm2 at 1064 nm (t = 15 ns), and no damage was observed at an irradiation power of 6 .0 kW and irradiation time of 10 minutes with the CW 1030 nm laser. From these results, we conclude that the AR coating is very useful for high-power laser applications.
[Key words] Anti-reflection Coating, High Power Laser, Laser Damage Resistance, Laser-induced Damage Threshold

Development of Super Soft Interconnector

As Crystalline Silicon Solar Cells become thinner, warping of the cells is a serious problem when cells are soldered to interconnectors during the modulation process. Therefore, an interconnector with low proof stress characteristics is in demand. In addition, there are demands to reduce the conductor size and to use lead-free solder alloys for the environment. We examined the conductive material, and examined each stage, such as the rolling condition, the solder plating condition, and the composition of the production line. As a result, we developed a super soft interconnector that largely decreased the 0 .2 % proof stress.
[Key words] Solar Battery,Cell,Interconnector,0 .2% Proof Stress,Solder Coated Rectangular Copper Wire

Development of A New Type of Partial Discharge Detector A006

Partial discharge occurs at defects such as voids, cracks and unusual concentration of electric fields in insulators of electric devices, electronic parts, power cables, etc. They accelerate the degradation of the insulators, and is the main cause of electrical breakdown. This can be prevented by detecting partial discharge, and the detection method is widely used for testing the quality of electric devices, electronic parts, power cables, etc. It is also used for researches such as electric insulating materials. Especially, in recent years, it is becoming increasingly important to detect partial discharge not only in high-voltage devices but also in low-voltage devices such as low-voltage motors.We have developed and introduce a new type of partial discharge detector using a low-frequency method, with improved performance such as linearity of electric charge, temperature characteristics, and new features such as easy data exporting to PCs, compared to conventional detectors.
[Key words] Partial Discharge, Insulator

Development of High Heat-resistant Magnet Wire(PI-MEXCEL®)

Based on the electro-deposition insulation techniques, Mitsubishi Cable Industries, Ltd. has developed fine rectangular magnet wires MEXCEL, which are provided to markets worldwide, mainly used as inductor coils for electronic devices. Recently, as electric devices become smaller and the trend shifts to hybrid cars and electric vehicles, MEXCEL is required to obtain higher heat-resistance. In addition to maintain the present electro-deposition insulation features, even insulation thickness and its high reliability, we have succeeded in developing a new fine rectangular magnet wire, called "PI-MEXCEL", which is competitive to AIW in terms of possessing high heat-resistance. This success is achieved by the development of higher temperature resistant electro-deposition insulation material, based on Polyimide. In this article, we introduce the development and the features of PI-MEXCEL as well as its applications.
[Key words] Electro-deposition, High Heat-resistance, Polyimide, Magnet Wire

Electromagnetic wave absorber technology and its applications for ETC

ETC(Electronic Toll Collection)started in March 2001, and shortly became nationwide as users increased. The utilization ratio has reached 80% as of June 2009. The ETC system in Japan uses a microwave absorber to control electric waves reflected from structures around the toll gates, roofs etc., to improve the communication environment.
With the expansion of traffic using ETCs, a more stable communication environment for electric waves is in demand. In recent years the problem includes, for instance, electric wave leakage to adjacent lanes in multi- row- ETC lanes, electric waves reflected by toll gate safety passages, etc. Moreover, because the expressway in cities are charged according to distance, ETC is set up at toll gate exits, and therefore microwave absorbers are required to be placed in various places. In this report, we introduce recent construction cases of microwave absorbers that our company has developed.
[Key words] ETC,DSRC,Electromagnetic Wave Absorber,Adjacent ETC-lane,Safety Passage,Free-flow

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