Optimization of complex for high-loss substance permittivity measurements

Test experiments carried out in clinical terms on measuring of dielectric data of human blood and evaluation of erythrocyte adrenergic activity showed that measuring complex on the basis of the developed before reflectometer possesses some failures to complete. A cuvette for biological objects loses stability of measuring at the intensive continuous duty (6-8 hours), and also at measuring of time dependence of complex permittivity (by series for 6 minutes). It was also shown that some features of material of patients have an influence on measurements, i.e. device sensitivity was not enough for statistically reliable differentiation of blood cells reaction on bioactive substances effect. Thus, it was required to rework measuring cuvette. For this purpose the series of calculation experiments were conducted to optimize the waveguide flanges structure of cuvette as well as to fit optimal gaskets thicknesses limiting the sample. It should be take into account sensitivity and feasible implementation of gaskets thicknesses. To simulate the electromagnetic processes in cuvette we used a software package developed in the department of mathematical physics of Institute of Radio Physics and Electronics of NAS of Ukraine. This software product allow calculating and studying the electromagnetic waves propagation in complex structures consisting, inter alia, of the dielectric of arbitrary shape with the known parameters of permittivity and conductivity. The results of calculating experiments represented at present work have been carried out by the finite difference time domain method (FDTD). Two-dimensional initial-boundary value problems are examined for the Epolarized field. Time-domain data are transferred into the frequency domain ones by means of the Fourier transform. A cuvette in a model experiment was the two-dimensional layer structure consisted of the test sample with limiting gaskets. It is located in a short-circuited from one end waveguide and fully filling its sect- - ion.