Mode Analysis of Miniaturized and Stopband-Enhanced Composite Electromagnetic Bandgap Structure for Power/Ground Noise Suppression

A miniaturized and stopband-enhanced composite Electromagnetic bandgap (EBG) structure is investigated by mode analysis for suppressing power/ground noise in PCB´s power distribution network. The composite EBG structure is constituted by the C-shaped EBG structure on power plate and the metal post periodically embedded in the substrate. The composite EBG structure improves both the lower bound cutoff frequency (f_L) and upper bound cutoff frequency (f_H) for wideband noise isolation. Due to the capacitance increase in the unit cell by the metal post structure, the f_L moves from 600 to 400 MHz. In addition, the composite EBG unit cell introduces a complex resonant cavity mode, bringing with the shifting of the f_H from 3.6 to 4.8 GHz. There is a good consistency between the simulations and measurements.