Improving the behavior of PCB power-bus structures by an appropriate segmentation

An effective and cost efficient method for suppressing cavity mode resonances within the power-bus of high-speed printed circuit boards is presented. It is shown that resonant modes can be completely suppressed by segmenting the power-bus into rectangular parts of smaller dimensions and connecting these parts suitably. For the case of identically shaped segments a double summation expression of the resulting voltage distribution within each part is derived. Furthermore, the impact of different connections between the segments is investigated. The theoretical results are well confirmed by measurements.