A method for extracting the 1-60 GHz dielectric spectrum of trace liquids using standard design coplanar waveguide sensing devices

Abstract This paper introduces a sensor designed for measuring the dielectric constant of small amounts of liquid. The sensor consists of a coplanar waveguide transmission line and an open container for the liquid, enabling broadband dielectric spectroscopy measurements for milliliter-scale liquids in the 1-60 GHz range. To improve the accuracy of dielectric spectroscopy testing, the sensor is calibrated using air and deionized water to obtain a coefficient matrix relating the sensor’s distributed parameters to the sample’s dielectric constant. This matrix is then used to calculate the dielectric spectroscopy of subsequent test samples. Tests on the dielectric spectroscopy of deionized water with this sensor and algorithm indicate that over the 1-60 GHz band, the error compared to previous literature results is within 5%, demonstrating the reliability of the proposed sensor and dielectric spectroscopy extraction algorithm.