Radiated noise measurement system to estimate the EMI regulations compliance of a power electronic circuit

One of the requirements that electronics circuits may satisfy are the conducted and irradiated noise specifications. While conducted noise is well covered in the literature, the radiated noise is not. Regulations about radiated noise impose limits in the noise measured three or ten meters far away the electronic equipment. These measurements are usually made in anechoic rooms, which are a very expensive equipment, and the measurement procedure is not a «plug-and-play» feature, but a carefully protocol of measurement is required. Once the electronic circuit has been tested, in case the regulation was not met, the designer unknowns the source of the problem, so the procedure to make the electronic circuit to comply with the regulation used to be a trial-and-mistake method, when the experience of the designer is essential. A new radiated noise measurement technique is proposed in this paper with two objectives: to simplify the measurement procedure and to have more information about the noise sources. The main idea is to scan the electric/field at two arbitrary but known distances. From these measurements, the Source Reconstruction Technique (SRT) allows the identification of the noise sources in the surface of the circuit and the field estimation at any distance, so that the regulation compliance can be evaluated. Moreover, if the regulation is not satisfied, the effect of the noise source modification can be tested, to find how the circuit must be modified to comply with the regulation.