On the Use of the Source Reconstruction Method for Estimating Radiated EMI in Electronic Circuits

Electromagnetic interference (EMI) regulations are a very important issue in the design of almost any electronic circuit. Over the years, “cut-and-try” procedures have been adopted by electronic designers to make circuits comply with these regulations, mainly due to the lack of reliable theoretical models of radiated noise and clear design rules. To gain new insight into this field, a novel approach is presented in this paper based on a well-known technique in the field of antenna design, i.e., the source reconstruction method (SRM). Its application allows a set of equivalent currents to be obtained that behave exactly like the circuit under consideration with regard to radiated noise. From these currents, magnetic and electric radiated fields can be obtained at any point in space, even at 3 or 10 m away from the circuit where the regulations must be met. Moreover, the equivalent currents accurately represent noise sources in the circuit, thus permitting the elements responsible for generating radiated noise to be located. The aforementioned method would enable designers to reduce the use of anechoic-chamber facilities when testing their designs, thereby leaving the chamber only for final certification purposes.