Dielectric properties of solid materials at microwave frequencies: specifics of practical application of the measurement methods

Specifics of practical use of the methods for measuring the dielectric properties of materials at different (factory and metrological) laboratories, and impact of such specifics on the measurements results have been considered. The measurements were performed at the factory radio physics lab of the Obninsk Research and Production Enterprise “Technologiya” named after A.G. Romashin, and at the metrology lab of the East-Siberian branch of the Federal State Unitary Enterprise “All-Russian Scientific Research Institute for Physical-Engineering and Radio Engineering Metrology.” The results of measuring the relative permittivity and dielectric loss tangent of solid material samples in the microwave range of electromagnetic radiation were analyzed. Based on the study results, the specifics of practical use of the standard methods for measuring the dielectric properties of materials have been established that were not described in the literature before. To perform measurements, circular waveguide resonators and standardized measurement procedures were used. The following two cavity resonator-based measurement techniques were applied: at a fixed resonance frequency (resonance tuning performed by moving a plunger), and at a fixed resonance length (resonance tuning performed by varying resonance frequency). These techniques were utilized at the factory and metrology labs, respectively. The results of measuring the dielectric properties of the samples showed good reproducibility and were consistent with the requirements for measurement methods. Lower reproducibility of the results was observed when measuring the dielectric properties of the samples of hygroscopic materials, materials demonstrating volumetric non-uniformity of properties, as well as in cases, when the diameter of the measured samples did not meet the measurement technique requirements. The obtained data can be used to improve the reproducibility of the results of measuring the dielectric properties of materials during practical application of the considered measurement methods.