Distributed Conversion of Common Mode into Differential Mode Interference

In this paper, the mechanisms that lead to the conversion of common mode RF interference into differential mode disturbances, which corrupt the information content of nominal signals and impair the operation of electronic systems, are investigated. To this purpose, distributed and lumped common mode-into-differential mode conversion mechanisms are discussed with reference to a simple test structure that can be analytically described. On the basis of the proposed analysis, the origin and the relative impact of such mechanisms is highlighted and the detrimental effect of distributed common mode-into differential mode conversion on the effectiveness of differential RF interference suppressing filters is discussed. Theoretical predictions are compared with experimental results.