Vol. 13, no.4, 2021
РусскийEnglish
RADIOELECTRONICS
PASSIVE MEASUREMENTS OF THE REFRACTIVE INDEX OF LIQUID NITROGEN AND FREE-FLOWING SUBSTANCES BY THE PRISM METHOD IN THE MILLIMETER WAVELENGTH RANGE
Valery A. Golunov, Konstantin V. Gordeev, Konstantin N. Rykov
Kotelnikov Institute of Radioengineering and Electronics of RAS, Fryazino Branch, http://fire.relarn.ru/
Fryazino 141190, Moscow region, Russian Federation
E-mail: golsnow@mail.ru, gordeev@yandex.ru, constrykov@yandex.ru
Received August 17, 2021, peer-reviewed August 27, 2021, accepted September 06, 2021
Abstract: It is proposed to use the classical prism method in the millimeter wavelength range for measuring the refractive index of liquid and free-flowing substances, including mixtures with particle sizes comparable to the wavelength. The method is implemented using a hollow radio transparent rectangular prism filled with a test substance. The measurements were carried out in the thermal radiation mode using radiometers with horn-lens antennas at frequencies of 37.5 and 94 GHz. To measure the deflection of the refracted beam, a linear scanner with a black body mounted on it, cooled with liquid nitrogen, was used. The distance between the prism and the scanner was 1 m. The refractive index of liquid nitrogen, sand, gravel, marble chips and granular polyethylene were measured. Using the refractive formula and the Landau-Lifshitz-Looeng formula for calculating the dependence of the refractive index of binary mixtures on the bulk density of particles, estimates of the refractive index of the material of the particles that make up the substances under study are obtained. They are in satisfactory agreement with the known experimental data for quartz, feldspar, granite, and marble.
Keywords: prism method, refractive index, millimeter waves, thermal radiation, mixtures of particles commensurate with the wavelength
UDC 535.36, 621.396.11
RENSIT, 2021, 13(4):435-442 DOI: 10.17725/rensit.2021.13.435.
Full-text electronic version of this article - web site http://en.rensit.ru/vypuski/article/413/13(4)435-442pdf