Dielectric Characterization of High-Temperature Liquids via Resonant Cavity Perturbation Technique

This paper presents a novel pumpkin-shaped resonant cavity sensor for high-precision dielectric property measurements in high-temperature liquids. The sensor employs a unique multi-cavity configuration with spherical resonant cavities arranged symmetrically around a central axis, and optimizes geometrical parameters and spatial distribution to effectively suppress higher-order modes and enhance axial electric field concentration. A specially designed quartz tube, capable of withstanding extreme temperature and pressure conditions, is precisely placed at the axial electric field maximum to act as a liquid container. Through comprehensive electromagnetic simulations and theoretical analysis, the proposed sensor exhibits excellent performance in complex dielectric constant measurements and shows great potential for reliable operation in high-temperature liquid environments. The sensor design is not only theoretically innovative, but also experimentally validated to demonstrate its feasibility for accurate dielectric characterization under complex thermal conditions. This innovative sensor design provides a new solution for the measurement of dielectric properties of high-temperature liquids, which is expected to play an important role in the fields of liquid state monitoring inside aerospace engines and aviation fuel quality assessment, and provides a high-precision tool for special environmental measurements in the aerospace field.