A millimeter wave dielectrometer for high loss liquids based on the Zenneck wave

• Published in: Measurement science & technology 2009-05, Vol.20 (5), p.055701
• Main Authors: Ganapolskii, E M, Eremenko, Z E, Skresanov, V N
• Format: Article
• Language: English
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/20/5/055701

The propagation of an electromagnetic wave in a dielectric rod placed in a high loss liquid was studied theoretically and experimentally. It is shown that the wave has a bulk character in the rod and a surface character in the liquid. The attenuation and phase velocity of this wave have strong dependence upon the dielectric properties of the liquid and the rod, while the phase velocity of this wave exceeds the light velocity in the rod material. It enables one to consider the studied wave to be similar to the Zenneck wave. A characteristic equation for the structure under study was derived and analyzed. The attenuation and phase velocity of this wave in the presence of distilled water and a water-ethanol solution were measured. Owing to these data, the real and imaginary parts of the complex permittivity of high loss liquids under test were determined. We have good agreement between the theoretical and experimental results. A differential dielectrometer based on the usage of the Zenneck wave was designed. Thus, the complex permittivity of high loss liquids with sufficiently high accuracy can be obtained. It is also possible to record a rather small difference between two similar liquids according to their dielectric properties.