Open-ended coplanar waveguide sensor for dielectric permittivity measurement

Abstract

A novel open-ended coplanar waveguide (CPW) sensor for dielectric permittivity measurement is presented in this paper. The open-ended CPW with flange is designed and fabricated on FR4 substrate. The admittance model that includes the radiation effect was used to describe the open-ended CPW sensor. Accurate dielectric permittivity measurements are obtained by using the three-material calibration technique, air, distilled water, and a 25% ethanol aqueous solution. Validation results on 50% and 75% ethanol aqueous solutions agreed with measurements by the commercially available open-ended coaxial-line probe.