Improved Experiment-Based Technique to Characterize Dielectric Properties of Printed Circuit Boards

Recently, an experiment-based traveling-wave technique to separate conductor loss from dielectric loss on printed circuit board (PCB) striplines, called the differential extrapolation roughness measurement (DERM), has been proposed. The further development of this procedure is presented in this paper. The new procedure is applied to both loss constant and phase constant, as opposed to the previous procedure, which is applied to only loss constant. A new roughness parameter QR to quantify conductor surface roughness has been proposed, and it is used in the improved procedure. This allows for more accurate extraction of dielectric constant and loss tangent over a wide frequency range. In this paper, the three sets of test vehicles are studied. Each set has three different types of copper surface roughness profiles; two of these sets are known to have the same dielectric, which is used for the validation of the proposed extraction procedure. The new corrected extracted dielectric parameters as functions of frequency for these sets of test vehicles are compared with those obtained using the previous DERM technique.