Statistical estimation of characteristic impedance distribution caused by PCB manufacturing process variation in high-speed mobile channels

In recent mobile systems, the fraction defective of the PCB channels increases with the increase of the PCB manufacturing process variation, when the other conditions affecting the PCB manufacturing are the same as before. From the experimental verification, we confirm that the distribution of the characteristic impedance is critically increased by the process variation. To reduce the fraction defective, we need to estimate the distribution of the characteristic impedance in the pre-design step as the criterion representing the deleterious effect of the process variation on the PCB channels. In this paper, we propose the statistical estimation method estimating the distribution of the characteristic impedance. Additionally, we define the noteworthy range of the characteristic impedance as the quantitative indicator representing the distribution of the characteristic impedance for the practical use.