Determination of the uncertainty of the radiated EMI predicted by measuring the absolute value of a magnetic near field

Uncertainty of prediction of radiated EMI of small equipment by means of the measurement of magnetic near field is investigated theoretically in the frequency range 30 - 960 MHz. In this paper a comprehensive set of different EUTs is constructed by means of two dipole moments. Each dipole moment combination thus characterises the radiation properties of one possible EUT. Different combinations are constructed by placing two dipole moments to a number of different polarisations and locations within the volume of the EUT. Dipole moment type may be electric or magnetic. Also the phase difference of the dipole moments is varied. Far field produced by each dipole moment combination is predicted using three different near-field to far-field transformations. Predicted far field in proportion to the real far field is computed, and PDFs of the far-field prediction accuracy are presented.