A Simple Nondestructive Radio Frequency Measurement Technique for the Analysis of Liquids

Dielectric resonators (DRs) are widely used in microwave and millimeter-wave applications, including antennas and bandpass filters. In this study, we exploit the properties of these resonators in a different way, demonstrating how a common container filled with liquid can be assimilated to a DR. The typical properties of DRs are used to investigate the physical and chemical properties of the content and their evolution, providing a contactless, noninvasive, and nondestructive evaluation (NDE) of its characteristics. The level of the liquid, its conductivity, and dielectric constant can be easily determined in real time, and used as parameters for in-line monitoring, quality control, and chemical composition assessment. Results are reported using a common wine bottle as a container, but are very easily transferable to other types of liquid containers, including plastic bottles or larger containers.