Controlled-Impedance PCB and Via Modeling

50 Ω single-ended and 85 Ω differential routes on an 8-layer FR-4 PCB.

Extracted the routes and evaluated via stubs, antipads, return vias, and TDR response.

Differential TDR peak reduced from 106 Ω to 92 Ω at a consistent 35 ps rise time.