PCB optimization focuses on designing boards to meet specific performance metrics while satisfying specific design constraints. In particular, interconnect design requires satisfying multiple design objectives and constraints that may be in conflict, and engineers need tools and methods to help them balance design these objectives while staying within their design constraints. For ultra-high-speed boards, designers need to optimize transmission line designs within the relevant signal bandwidth, which can extend to hundreds of GHz. Newer signaling specifications and standards (e.g., USB4, DDR5, and IEEE 802.3 standards) require this type of optimization. In this presentation, the use of model extraction, design exploration, and fusion of analytical/numerical models will be presented with the goal of developing models for broadband design optimization. For PCB transmission lines, a model that accounts for copper roughness and dispersion with numerical or analytical impedance models will be presented. These concepts fit within recent research on novel CAD and field solver methodologies to address high speed/high frequency interconnect design challenges.