Mandatory Internship High-Speed PCB Test Structures for Resin Skew Characterization

Modern automotive systems operate at data rates exceeding 16 Gb/s, where small variations in PCB materials can significantly affect signal integrity. One important effect is resin skew, caused by the inhomogeneous distribution of glass fibers and resin in PCB laminates. Differential signals propagating over glass bundles versus resin pockets experience different propagation velocities, leading to timing skew and potential eye-diagram degradation.

This internship investigates measurement-based characterization of resin skew using dedicated high-speed PCB test structures. The goal is to design, simulate, and analyze differential test structures that allow quantifying skew induced by glass weave and resin distribution. The work contributes to developing standardized measurement structures for reliable high-speed interconnect design and material selection.

• During your internship you will delve deeply into the subject matter by conducting comprehensive literature reviews on fiber optic effects and resin-induced propagation delays in high-speed printed circuit boards.
• You will independently perform precise VNA (vector network analyzer) measurements on test coupons to determine the broadband S-parameters.
• Meticulously you will analyze the measured and simulated S-parameters to precisely determine the propagation delay and differential propagation delay.
• Furthermore you will systematically investigate the influence of fiber optic weave, trace orientation, and routing geometry to uncover optimization potential.
• Lastly you will document your findings clearly and use them to develop improved characterization structures that will advance our development.