Effects of Calibration and De-Embedding on Material Parameter Extraction Using Coaxial Airline

Electrical characterization can involve many different parameters but here we will focus on material permittivity and permeability. Measurements using coaxial airline have been around for a long time and are included in some commercial software for parameter extraction, such as Keysight N1500A. In this paper, we examine the effects of various approaches to calibration and de-embedding of the measurements in the $2-18 \text{GHz}$ range. The coaxial airline used has APC7 connectors and the best results are expected when using a calibration kit for that set of connectors. In practice, however, many labs may only have calibration kits for 3.5 mm or SMA connectors. In this case, adapters must be used to connect to the APC7 airline, and they must be deembedded. We report on our observations of how well different calibration and de-embedding techniques perform when used in conjunction with material parameter extraction software. Our intended application is characterization of microwave absorbers, and we examined the extraction procedures that deal with both permittivity and permeability.