Dielectric Material and Foil Surface Roughness Properties Extraction based on Single-Ended Measurements and Phase Constant (\beta) Fitting


Dielectric substrate and foil surface roughness properties of fabricated printed circuit boards (PCB) are important for high-speed channel design. Several stripline-based extraction methods have been developed to characterize dielectric relative permittivity (\varepsilon_{r}), dielectric dissipation factor (\text{tan}\delta), and foil surface roughness correction factor (K_{R}) using measured S-parameters. However, the \text{tan}\delta extraction still needs further improvement due to the difficulty in separation of dielectric and conductor loss. The authors found that the frequency-dependence of the stripline phase constant (\beta) is helpful to determine the \text{tan}\delta without introducing high sensitivity to foil surface roughness. By introducing a causal dielectric frequency-dependent model, \varepsilon_{r} and \text{tan}\delta are extracted by fitting measured \beta. The foil surface roughness property (correction factor K_{R}) is obtained using the conductor loss calculated by subtracting extracted dielectric loss from the total loss. To demonstrate the feasibility of the proposed method examples are provided using simulation data and fabricated PCB.

Meeting Name

2020 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity, EMCSI 2020 (2020: Jul. 27-31, Virtual)


Electrical and Computer Engineering

Keywords and Phrases

Dielectric Material; Foil Surface Roughness; Printed Circuit Boards; Signal Integrity; Skin Effect; Striplines

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2020 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

10 Sep 2020