Development of a magnetic field measurement system using a tri-axial search coil

In order to measure the magnetic field noise around electric devices, we developed a measurement system using a tri-axial search coil. The crosstalk of the orthogonal search coils is less than -40 dB between the tri-axial search coil sensors. The measured magnetic sensitivity of the search coil is 10 pT//spl radic/Hz at 1 kHz.

I. Introduction

Recently, the use of electromagnetic waves is increasing in the technologies of electronics, information, and communications. It is believed that electromagnetic waves leaking from some electric devices may cause incorrect operation of other electric devices and may have some influence on a human's body. Therefore, we have to prevent these electromagnetic noises from affecting devices or our body, and it is necessary to shield out the magnetic field. We can prevent these electromagnetic noises using the shielding materials. But if we do not know the strength of the magnetic field that is leaking from the electric devices, we can not effectively prevent the noises. Therefore, we have to develop the shielding sheets considering these things so that they are appropriate for the purpose at hand.