Summary
International Symposium on Antennas and Propagation
2010
Session Number:2WD1
Session:
Number:2WD1-1
The Effect of Via Spacing on the Signal Integrity Performance of PCB with Slotted Ground
Soonyong Lee, Wonbum Seo, Jaehoon Choi,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
Recently, there has been growing interest in the effect of slotted ground plane structures on the SI performance of PCBs. It is common to create slots in power/ground planes in high-speed printed circuit board (PCB) designs. In mixed signal circuits, split power/ground planes can isolate a noisy digital circuit from a sensitive analog circuit. Slots in the power/ground planes are also employed in PCBs with multiple power supplies in order to provide the DC isolation among different supplies[1]. However, slotted ground planes can give rise to electromagnetic interference (EMI) and distortion of original signals because a slot in a conducting plane can generate unwanted radiation that can easily couple to nearby signal traces. The slot can also pick up undesired energy from the surrounding circuits and couple this energy into the signal traces that cross over them. Moreover, in some packaging, it may not be possible to avoid routing signal traces over slotted ground plane because of strict space requirements[2]. In this paper, the effect of via spacing on the signal integrity of PCB with a slotted ground is investigated using Finite-Difference Time-Domain (FDTD) method based CST Ver. 2010[3]. For this purpose, via spacing and number of via around slotted ground are used as parameters for performance analysis. The signal integrity performance of FR4 PCB microstrip line through slotted ground with and without optimized via structure is evaluated. Test boards are fabricated and Sparameter and eye-diagram characteristics are measured to validate the effectiveness of the optimized via structure for signal integrity improvement.