Dielectric Constants of PCB Cores & Prepregs

Material and process variations in multilayer PCBs impact transmission line impedances. With fast TDR-based measurements, dielectric properties can be accurately extracted — no time-consuming lab work like analyzing cross-sections required.

DTDR-65 setup for dielectric constant measuring using a test coupon. DTDR-65 setup for dielectric constant measuring using a test coupon.
Microstrip line TDR-measurements for dual-length evaluation. Microstrip line TDR-measurements for dual-length evaluation.
Gerber file view of dielectric test coupon layout for PCB fabrication. Gerber file view of dielectric test coupon layout for PCB fabrication.
Close-up view of a dielectric test coupon with unscrewed SMA connector used for dual-length TDR evaluation. Close-up view of a dielectric test coupon with unscrewed SMA connector used for dual-length TDR evaluation.
Dielectric test coupon with high precision RPC-3.5 connectors. Dielectric test coupon with high precision RPC-3.5 connectors.
Dielectric porperties and corresponding dual-length TDR traces in SeunisPro. Dielectric porperties and corresponding dual-length TDR traces in SeunisPro.
Close-up view of a dielectric test coupon used for dual-length TDR evaluation. Close-up view of a dielectric test coupon used for dual-length TDR evaluation.

What types of substrates can be measured?

  • Cores & prepregs
  • FR-4, low loss materials, PTFE based, etc.
  • Not limited to materials manufacturers

How does it work?

  • Innovative dual-line technology
  • Dedicated delta L test coupons (generated by Seunis software)
  • Dielectric properties & wave impedance vs. frequency
  • Single-ended measurements with STDR-65 or DTDR-65