A method of evaluating magnetic field strength by correction between uniform and non-uniform field in near-field

Abstract

This paper describes a new method for predicting the magnetic field strength in near-field for complex exposure situations. The measurement of the exposure level for compliance tests at sites close to a current source in the low frequency range is restricted by an abrupt gradient distribution in the field strength, non-uniform characteristics, and spatial averaging of adjacent field values. By applying the concept of calculating the induced current density on or in a human body, the magnetic field strength in near-field can be determined using the measured field strength obtained in far-field. This calculation uses the magnetic flux densities from a current source of infinite line type and the coupling factors determined beforehand. The calculated magnetic field strengths are compared with measurement values. The maximum difference is no more than 0.0174 A/m.