Multipolar expansion sensors for near field characterization

This paper introduces a new generation of magnetic field sensors, based on the spherical harmonics decomposition concept. The measurement principle is similar to a spatial filtering: according to the coil shape, the sensors are just sensitive to a specific component of the multipolar expansion. Five coil shapes are determined, in order to account for the first two orders of the harmonic decomposition. The way of determining the coil shape is first explained, and a validation is proposed using a finite element software.