Impact of Shorting Vias Placement on Embedded Planar Electromagnetic BandGap Structures Within Multilayer Printed Circuit Boards

Abstract

This paper investigates the power integrity behavior of planar electromagnetic bandgap (EBG) structures embedded between two solid layers within the stack-up of a multilayer printed circuit board. The bandgap generation and power integrity performance of the embedded EBG can be achieved only by placing vias shorting the solid planes above and below the patterned layer. The vias inhibit the resonances of the cavity made by the two solid planes, ensuring the designed bandgap, as if the planar EBG was laid out on an outer stack-up layer. The impact of the stitching vias' number and location is addressed and the concepts of regular, global, random, or local via placement are introduced. Index Terms-Electromagnetic bandgap (EBG), embedded EBG, power integrity, via placement.

Mitigation of Noise Coupling in Multilayer High-Speed PCB: State of the Art Modeling Methodology and EBG Technology

“…The isolation at the EBG layer is needed between the vias and the patches, and it is achieved by etching circular ring around the vias. A detailed procedure on how the number of vias and their location need to be chosen for achieving the desired bandgap is given in [58]. The embedded EBG cavity presents the same cavity resonances below the bandgap, as the outer EBG counterpart, thus the bandgap lower limit can be designed as shown in [59], [60].…”

“…The EBG layer layout introduced in [55] is considered, whereas the properties and details of the embedded geometry are given in [58]. Three test boards are built regularly placing 13, 25, and 41 vias for shorting the top and the bottom solid planes.…”

“…The via-to-via distance decreases when placing more vias, and the coupling between the two test ports can occur just when energy is able to pass across two adjacent vias. Therefore the f high is related to the distance between two adjacent vias [58]. The case with 41 vias is characterized by a first resonance of the two solid planes cavity at 6.8 GHz, but the bandgap can be considered to end at the first resonant mode of the single patch cavity in the unit cell occurring at around 4.8 GHz (resonance obtained also in the other two cases).…”

A compact customizable tunable EBG filter

“…It remains a challenge to design and fabricate small size tunable filters for handheld devices working in commercial frequency bands. EBG filters/resonators [8,9,10,11,12,13,14,15,16] have attracted a lot of attention due to its high Qu (Unloaded Quality Factor), ease of integration with other RF front end components and low cost. Most recently, a Compact Configurable EBG (CEBG) filter was demonstrated to function at specifically selected working frequency by simply adjusting an external capacitor by this group [17,18].…”

Vertical Cascaded Planar Ebg Structure for SSN Suppression

“…But the bandwidth of these structures is limited. At present, some researchers have embedded EBG structure between two layers of ground to get a better suppression solution [15][16][17]. Although the effect has been improved, it does not achieve the capability of the ultra-wideband SSN suppression.…”