DOI: 10.1109/TMTT.2025.3592883   IEEEXplore: https://ieeexplore.ieee.org/document/11106233  

A novel sensing setup for broadband dielectric spectroscopy (BDS) of liquids featuring a 3D-printed test tube with a central metal pin to hold the sample, and a complimentary jig to hold the tube and ensure coaxial transmission line operation.

0.01–15 GHz

A resin 3D-printed test tube featuring 0.4 mm thick wall that was established to be sufficient to maintain mechanical integrity, a drilled 0.5 mm radius hole in the bottom for the central 0.4 mm radius sensor wire to pass through, and a 4 mm thick solid bottom layer that was determined to be thick enough to avoid sample leakage. The complimentary test jig that incorporates a spring-mounted pin to contact the test tube wire and copper cladding in the tube cavity to ensure coaxial line operation. A three tier calibration method that de-embeds the feeding network part of the jig and establishes two geometry-related constants derived by measuring two reference liquids of known dielectric properties.

Noncontact dielectric spectroscopy of liquids via reflection coefficient analysis with high sensitivity and resolution over a wide frequency range for samples that are highly viscous, dense, or poorly soluble.

Permittivity determination uncertainty of ±0.55 real and ±0.40 imag. (in-band average standard deviation).