Application of modified waveguide sensor for dielectric study of red blood cells of patients with discirculatory encephalopathy before and after the therapy

Abstract

The paper describes the EHF dielectrometry method which is used for study of dielectric characteristics
of human red blood cells (RBCs) in the free water dispersion region. This method is based on
measurement of complex reflection coefficient from short-circuit multilayer structure (waveguide sensor)
containing the sample in the single-frequency mode (39.5 GHz). An improved in their accuracy
characteristics waveguide sensor has been used. For a given sensor the problem of finding the complex
permittivity has been solved for the first time and realized by solving the direct and inverse problems of
electrodynamics using numerical methods. The direct problem of finding the complex reflection
coefficient was solved by the finite-difference time-domain (FDTD) method. This method makes it
possible simulating the measuring structures of arbitrary shape containing the sample under study. The
inverse problem is implemented by solving a system of nonlinear equations. The algorithm developed has
been successfully applied by the authors for the sensor calibration, which allowed use in the study of the
dielectric characteristics of the blood. As an example of feasible application of improved sensor the
results of measurement dielectric characteristics of RBCs of patients with discirculatory encephalopathy
before and after therapy are represented. It has been revealed an increasing their complex permittivity,
which indicates a change of water state in the cells in the dynamics of therapy. There was a significant
increase in the complex permittivity, which indicates a change of water state in the cells as a result of
medical treatment. The data obtained demonstrates the opportunity of using EHF dielectrometry while
evaluating the state of the patient’s blood cells during their rehabilitation.