Using spherical near field measurements in computational EMC

Abstract

Inverse source or equivalent current/source method (EQC) provides an accurate near-field representation of any radiating device in terms of equivalent electric and magnetic currents [1–4]. Starting from measured near or far field data in any measurement configuration, this technique allows to determine an accurate 3D electromagnetic model, maintaining the near field (NF) and far field (FF) properties of the measured device. The equivalent model of the device find use as measured source in commercial computational electromagnetic (CEM) solvers in form of a near-field Huygens Box [5]. Of special interest to the EMC community, equivalent current representation of measured devices are directly applicable in diagnostics/hot-spot finding and in the determination of radiated emission at any distance. The Huygens Box, derived from measurements, is applicable in the simulation of emission in different scenarios when the device is in vicinity of different objects such as shielding, cables etc. This paper shows the study of the emission of a representative printed circuit board (PCB) based on commercially available near field measurement system, post-processing and CEM tools.