Electromagnetic sensor for measuring the dielectric permeability of materials

Relevance: Problems of control and determination of electrophysical parameters of materials of different physical nature are relevant in terms of the development of express methods of analysis of substances in various fields of science and technology, in particular, in biotechnology and biomedicine. Also, the relevance of the work is grounded by the search and implementation of new non-invasive medical diagnostic methods. The purpose of the work is to experimentally test the method of calculating the dielectric constant of multilayer structures based on conformal transformation, to test the method of electromagnetic probing of objects with one-side access using a microstrip resonator. Materials and methods: The paper presents a method for calculating the effective dielectric constant of a three-layer structure using a microstrip resonator of a new shape. A number of solid and liquid materials were investigated experimentally. It is shown that the resonant frequency and quality factor of the resonator loaded with the investigated material allow to estimate the concentration of the components of binary solutions. The possibility of using a microstrip resonator as a plethysmographic sensor has been investigated. Results: An electromagnetic sensor for measuring the dielectric constant of objects with one-side access was developed. The description of the original design of the microstrip resonator is presented and its modeling and experimental research are carried out. The results of measurements of the dielectric constant of objects of different physical nature are obtained: solid dielectrics and biological liquids. The influence of relative glucose concentration on the resonant properties of the sensor was studied. The possibility of using the sensor as a plethysmographic sensor in biomedical systems is shown. Conclusion: Theoretical and experimental studies of a microstrip resonator of complex geometric shape, which are presented in the paper, confirmed the possibility of its use as a sensor of electrophysical parameters of materials with different dielectric constant and conductivity. A new method of blood flow registration is proposed, based on the fixation of changes in the effective dielectric constant of tissues containing blood vessels.