Equivalent dipole models of electromagnetic emissions from near-field scanning

This paper gives an introduction to the concept of equivalent dipole modelling of the emissions of electronic equipment. To simplify the computation of emissions from electronic devices an equivalent model of the device based on a dipole array is derived using the measured emissions in the near field. The requirements for the near field scanner and the methodology for deriving the equivalent dipoles are described. It is shown that artifacts of the ground plane such as reflection and diffraction can be accounted for using passive dipoles related to the finite ground plane and the location of the source dipoles.