Wideband extraction of Dk and Df of printed circuit boards using two transmission lines with sufficient length difference
- Resource Type
- Conference
- Authors
- Kuen-Fwu Fuh; Bo-Jiun Tsai; Liu, Annie; Liao, Eric
- Source
- 2012 7th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT) Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT), 2012 7th International. :287-290 Oct, 2012
- Subject
- Components, Circuits, Devices and Systems
Computing and Processing
Engineered Materials, Dielectrics and Plasmas
Fields, Waves and Electromagnetics
Photonics and Electrooptics
Signal Processing and Analysis
Propagation constant
Transmission line measurements
Conductors
Scattering parameters
Vehicles
Stripline
Permittivity
- Language
- ISSN
- 2150-5934
2150-5942
Two striplines that have identical cross-section and sufficient length difference were used in this investigation as a test vehicle to extract permittivity of printed circuit board. The extraction procedure for Dk and Df follows the algorithm of conventional TRL calibration to firstly extract the frequency-dependent propagation constants of the test vehicle; then the values of Dk and Df at each frequency point are extracted from them by the aids of empirical models of stripline structure. The issue of limited frequency span resulted from numerical ill conditions that generally occurred for TRL-calibration procedure was significantly reduced by introducing sufficient line loss. Increasing the length difference of the test vehicle would introduce more line loss and stabilize the recovering procedure; therefore the extraction bandwidth was immensely increased. Since only two signal-ended striplines are used, this procedure could also save the estate of PCB occupied by the test vehicle, time and cost required for the test measurement. This procedure is also suitable for characterizing temperature-dependent variations of Dk and Df since vector network analyzer calibration is not needed, and un-calibrated S-parameters of the two test lines can be used to correctly extract the permittivity of PCB if proper successive average was applied.