Signal via transition is inevitable in backplane multi-layer board for high density routing. And a significant simultaneous switching noise (SSN) coupling to a signal occurs through the signal via transition. In this paper, we present suppression method of the SSN noise coupling caused by via transition in multi-layer backplane board using electromagnetic bandgap (EBG) structure. EBG structures are vertically located around a signal via to provide the low power/ground impedance area. The low power/ground impedance area suppresses the noise propagation and reduces the SSN noise coupling. It is shown that, within the stopband, the power/ground impedance at the position of the signal via with EBG structures is free from the power/ground planes cavity resonance, and the SSN coupling in single-ended and differential signaling is suppressed.