Differential Extrapolation Method for Separating Dielectric and Rough Conductor Losses in Printed Circuit Boards


Copper foil in printed circuit board (PCB) transmission lines/interconnects is roughened to promote adhesion to dielectric substrates. It is important to characterize PCB substrate dielectrics and correctly separate dielectric and conductor losses, especially as data rates in high-speed digital designs increase. Herein, a differential method is proposed for separating conductor and dielectric losses in PCBs with rough conductors. This approach requires at least three transmission lines with identical, or at least as close as technologically possible, basic geometry parameters of signal trace, distance-to-ground planes, and dielectric properties, while the average peak-to-valley amplitude of surface roughness of the conductor would be different. The peak-to-valley amplitude of conductor roughness is determined from scanning electron microscopy images.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Conductor Loss; Copper Foils; Data Rates; Dielectric Substrates; Differential Methods; Dissipation Factors; Extrapolation Methods; Geometry Parameter; High-Speed Digital Design; Loss Tangent; Scanning Electron Microscopy Image; Signal Traces; Adhesion; Dielectric Losses; Dielectric Materials; Organic Pollutants; Scanning Electron Microscopy; Scattering Parameters; Substrates; Surface Roughness; Printed Circuit Boards; Conductor Surface Roughness; Dielectric Constant (DK); Dissipation Factor (DF); Loss Tangent; Printed Circuit Board (PCB); S-Parameters

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version


File Type





© 2012 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Apr 2012