N. L. Yevich, Yu. V. Prokopenko
The work is dedicated to research of the features of the field which formed by the radiowave radiator of millimeter band. In an approximation of a given current the expressions describing the fields formed by the radiator in object of the control within the limits of intermediate and distant zones of diffraction are obtained. The capability of the permittivity value measurement of object of the control by the period of variation of a field which received under some definite angle is demonstrated. The results of experimental researches are submitted. The estimations of errors of measurements conforming to the realized techniques are adduced. The comparison of results of experimental researches of features of the fields excited by the radiator with a variable geometry with the data, obtained by a way of the mathematical modelling is submited. The range of angles is determined, within the limits of which one the minimization of errors of the control is provided. The maximum effective usage conditions of the radiator with the purposes of radiowave permittivity measurement are determined. The maximum measuring error of the permittivity absolute value by a radiowave method, which proposed, does not exceed 2,24 %, that it is quite enough for usage of a method with the purposes of a non-destructive technological testing, defectoscopy and defectometry. The results of measurement of the real part of dielectric permittivity value and tangent of the loss angle of plexiglas and engine oils obtained by a global minimization method are adduced. The presented data well agreed with the most authentic earlier published data. The possibility of the engine oils quality control on the tangent of the loss angle is demonstrated.