Kazuo Murakawa

Analysis of electromagnetic fields in and around buildings equipped with shielding screens

The effectiveness of electromagnetic shielding screens installed in buildings as electromagnetic noise countermeasures depends on their structure, position, and the frequencies of the electromagnetic noise. To numerically estimate the effect of shielding screens, we constructed wire-grid models of the buildings, modeling the shielding screens as plane surfaces. We then used the method of moments to calculate the electromagnetic fields in and around those models. The calculated results agree well with measured results, demonstrating that the shielding effect of shielding screens can be estimated by using this method.<<ETX>>

Reducing lightning current using surge protector for telecommunications cables

We describe the effectiveness of surge protective devices (SPDs) for telecommunication cables and evaluated them in a full-scale experiment and a field test against lightning surges. Because the extent of the impact of communication failure is wide due to lightning damage to telecommunication cables, an effective countermeasure is required. An SPD is installed in connected splicing closure installed in the branch point and the cable end of a telecommunications cable. We also clarified that the lightning damage rate of telecommunications cable decreased to about 1/3, and the lightning damage rate of telecommunications equipment decreased to about 1/5.