A Novel Compact Electromagnetic Bandgap Structure in Power Plane for Wideband Noise Suppression and Low Radiation

A compact reduced unit cell size electromagnetic bandgap (EBG) power plane, realized with a combination of alternating impedance EBG and multiple narrow slits, is presented. By concatenating 2 x 2 high-frequency unit cells, a virtual low-frequency EBG unit cell is synthesized without changing the overall dimensions. In this configuration, the basic slit in the high-frequency unit cell remained same, and an additional slit with longer dimensions is added in parallel to the basic slit by synthesizing a larger low-frequency unit cell. EBG is characterized for its dispersion diagram, noise suppression, signal integrity, and electromagnetic radiation. Fabricated EBG exhibits a bandgap from 0.9 to 3.5 GHz with isolation better than -40 dB over the band. Radiated emission of the new EBG is small with an average value of 35 dB.uV/m. Compact EBG also exhibits low impedance, which is less than 1 Omega over the stopband. Eye patterns are generated to analyze signal integrity issues when the data lines are referenced over the solid ground plane and EBG plane. The degradation of the maximum eye opening and the maximum eye width for the proposed EBG power plane at 2 Gb/s data rate is about 17.8% and 1%, respectively, with reference to the equivalent board with solid power plane.