Electromagnetic Band Gap structure for cut off of low frequency noise in 3-D printed circuit board

This paper describes the design of mushroom EBG (Electromagnetic Band Gap) structure within slit defected on power supply plane in order to control PI (power integrity) for realizing high-density multi-stacked printed circuit board. Generally, EBG structure is not suitable to block the low frequency noise around 1GHz in the printed circuit board, because EBG structure requires large area to cutoff low frequency noise. In this paper, new type of mushroom EBG structure, which has slit defect on power supply plane, to increase inductance for EBG function was proposed. By applying the new mushroom EBG structure of small patch size 10mm × 10mm × 3 pieces in the 0.9 mm thickness printed circuit board, we realized -40dB isolation at stop band frequency 0.94GHz~1.25GHz. Consequentially, the multi-stacked printed circuit board thickness could be reduced to 81% of using conventional mushroom EBG structure.