年間 12 号発行
ISSN 印刷: 0040-2508
ISSN オンライン: 1943-6009
Indexed in
DIELECTROMETER CUVETTE WITH HIGH DIFFERENTIAL SENSITIVITY BASED ON CIRCULAR WAVEGUIDE WITH A DIELECTRIC INSERT INTENDED FOR HIGH LOSS LIQUIDS
要約
The complex permittivity of strongly absorbing liquids (e.g., water and aqueous solutions of various substances) needs to be known in various fields of science and engineering, where such liquids are used. Previously, we proposed a waveguide-type measuring cuvette, which is a dielectric (quartz) cylinder immersed in the test liquid and developed a highly sensitive 8-mm band dielectrometer with such a cuvette. Theoretical and numerical analysis of the proposed cuvette was conducted without considering the external border of the cuvette, which was the subject of discussion while comparing it with the experiment results. In this paper, we address this shortcoming, and conducted theoretical and numerical study of electrodynamics parameters of the dielectrometer cuvette with taking into consideration of its external borders. This cell is formed by a circular metal 8-mm band waveguide with a coaxial cylindrical insertion of a low-loss dielectric. The investigated liquid fills the space between the surfaces of the insert and the waveguide. To increase the sensitivity of the cell to the changes in the concentration of substances in a test high loss liquid we used sufficiently thin layer of it (of the order of quarter wavelength), in which the wave interference is observed. The result shows that the cuvette with the layer of absorbing liquid, wherein a penetration depth is commensurable with the thickness of the liquid of the layer, has an increased differential sensitivity. Compared with known technical designs the suggested structure has advantages when used in precise dielectrometer of strongly absorbing liquids.