Measurement of the magnetic field in the near-field region and self-inductance in free space due to a multiturn square-loop

A low-power electromagnetic multiturn square-loop transmitter-receiver system has been developed to measure the topographical features of a human torso. The paper presents a theoretical analysis of the magnetic field, and derives equations to calculate the self-inductance caused by a three axis orthogonal multiturn square-loop transmitter and receiver. The theoretical and experimental results of the magnetic field are compared at distances ranging from 8 to 26 cm. Results indicate that the strength of the magnetic field on the coaxial arrangement is double that for the coplanar arrangement. The errors of the results on all three axes are less than 1%. Measurement of the inductance shows that more accurate results are obtained for smaller sizes and for a greater number of turns of both transmitter and receiver