CIRCUIT BOARD, METHOD FOR REDUCING EMI OF CIRCUIT BOARD AND METHOD FOR REDUCING EMI OF ELECTRONIC APPARATUS USING THAT CIRCUIT BOARD

摘要

PROBLEM TO BE SOLVED: To obtain a circuit board having a wide conductor pattern for use in a power supply/ground layer, in which radiation of unnecessary electromagnetic wave from that pattern due to common mode resonance is reduced. SOLUTION: A circuit board having a wide conductor pattern of a power supply pattern 26 and a ground pattern 25 is provided with an additional conductor 20 projecting from the corner part of the wide conductor pattern, while being coupled electromagnetically therewith so that the linear length of the conductor contour is lengthened electromagnetically at the corner part. The additional conductor 20 may be provided in the same layer as the wide pattern or a layer different therfrom. The additional conductor 20 can suppress common mode resonance of the wide conductor pattern to reduce radiation of unwanted electromagnetic waves from the circuit board.