DIELECTRIC PROPERTIES OF WATER SOLUTIONS WITH SMALL CONTENT OF GLUCOSE IN THE MILLIMETER-WAVE BAND AND THE DETERMINATION OF GLUCOSE IN BLOOD

摘要

To determine the complex permittivity, i.e. ε' and ε", of a medium, using noninvasive methods one has to measure two parameters of the reflected electromagnetic wave. Usually (see, for example, [1]), one employs a sophisticated and expensive vector network analyzers and measures the modulus, |r|, and phase, Φ, of the reflection coefficient, R{sup}*=|r|e{sup}(iΦ) (|r|{sup}2 is the power reflection coefficient). However the measurement of the phase, Φ, of the reflection coefficient is not easy, and the error of it reaches up to ±5 grad. For this reason, common measurement technique cannot be used for a noninvasive measurement of small glucose concentration in water. Here we use a sufficiently simple scheme for determining ε' and ε" of a medium, which consists in measuring the modulus, |r{sub}(min)|{sup}2 = R{sub}(min), and frequency, f{sub}(min), of millimeter (MM) wave (f{sub}(min), corresponds to the minimum of the reflection coefficient R{sub}(min),) from the following structure: plane-parallel matching plate made of a low-loss dielectric - a medium under measurement with high losses. It was developed computer programs to calculate the dielectric properties of the medium under test from the measured R{sub}(min) and f{sub}(min) and experimental setups.