It can be expected that a coplanar waveguide (CPW) bend would present different transmission characteristics from those of a microstrip-line (MSL) bend because, unlike MSL, CPW has a signal conductor and two ground conductors on the same side of the substrate. This paper describes the transmission characteristics of bended lines, especially CPW bends formed on a printed circuit board. Transmission characteristics of angular and circular CPW bends of various bend angles are studied and compared with those of straight lines and MSL bends of the corresponding structures. There are dips in the transmission level in the CPW bends, but they are not found in the straight lines and MSL bends. The cause of these dips is explained in terms of the path-length difference of the two slots along the bend. Also, it is proposed that the transmission characteristics can be improved by using a CPW bend with an offset inner conductor. Results of measurements show that the proposal is useful.

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Power saving of digital systems as the laptop computers by using butteries should be considered for carrying and long time operation. Hence, power saving semiconductor devices have been developed for this purpose. On the other hand, power save managements have to be considered by power control of the circuits. But, it has not been performed effectively because users are required to have very high knowledges to perform it. Then in this paper, we develop a CAE system for the power save design of digital systems. It is effective to simulate the power saving digital systems and it gives useful directions for the electronic circuits and PWB designs.

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[in Japanese]

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We have developed a new method of fabricating a multilayer wiring structure. Conventionally, the insulation layer was fabricated first, and then through-holes were formed and filled with a metal. In our new technique, through-hole posts were fabricated first, followed by the fabrication of the insulation layer. This technique offers a smooth surface which was independent of the thickness of the lower wiring conductor.

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