Model and Mechanism of Miniaturized and Stopband-Enhanced Interleaved EBG Structure for Power/Ground Noise Suppression

An interleaved electromagnetic bandgap (EBG) structure is investigated to be with a compact size and wide stopband bandwidth for suppressing power/ground noise in power distribution networks. A design concept of the interleaved EBG structure is given to improve both lower and upper bound cutoff frequencies through varying the pitch of the power and ground vias and validated by measured results. An equivalent circuit model of the 1-D EBG structure is established using transmission-line sections to precisely predict the lower and upper bound cutoff frequencies. Based on the 1-D model, a physical mechanism is found to explain why the interleaved EBG structure can reduce the size and broaden the stopband. As an example, the bandgap of the interleaved EBG structure is in the range from 1.9 to 4.54 GHz. The electrical size, which is normalized to the wavelength in the substrate, and relative bandwidth are 0.071 λgL and 139%, respectively. Unlike other works with tradeoff between size and bandwidth, the interleaved EBG structure can simultaneously achieve substantial improvements on the bandwidth of 51.1% and on the miniaturization of 61.2% compared with the conventional mushroom-like EBG structure.