Modeling and analysis of a conventional and localized electromagnetic bandgap structures for suppression of simultaneous switching noise

The transmission line method (TLM) is applied for the analysis of a conventional electromagnetic bandgap (EBG) and enhanced moat structures with an arbitrary shaped power/ground plane. Fast and accurate modeling by TLM reveals computationally efficient results as compared to 3D full-wave electromagnetic analysis. Moreover, it is shown that the suppression bandwidth of an EBG structure can be easily analyzed with stepped impedance filter approach, and the calculated bandwidth is identical to the measured bandwidth. In general, the conventional EBG structure provides highly efficient suppression of simultaneous switching noise (SSN) over the broadband range; however, it is difficult to apply this concept to real PCB design for high-speed digital circuits due to degeneration of the signal integrity (SI) performance. In this work, an enhanced localized EBG structure is suggested to enlarge the suppression bandwidth by modifying the EBG pattern without causing any SI problem. The number of bridges for each pattern is minimized, and a meander-shaped bridge is used to increase the inductance of the bridge. As a result, good suppression of SSN is achieved from 0.8 to 6.5 GHz with a -25 dB suppression level.