A high signal integrity interconnect design using a genetic algorithm and its solution analysis: What solution did GA find in time and frequency domain?

In the GHz domain, conventional printed circuit board (PCB) trace designs based on the matching of characteristic impedances do not work well for signal integrity (SI) improvement. In order to overcome this difficulty, we previously proposed a novel PCB trace structure, the segmental transmission line (STL), in which the trace design is optimized using genetic algorithms (GAs). In this paper, we apply the STL to the end-to-end transmission systems such as used in PCI-express, USB, SATA, and demonstrate its high effectiveness on the SI improvement by measured eye-diagrams on its prototype. Furthermore, we also measure s-parameters of the prototype and show what design solution the GA found.