Quasi-optical dielectric resonators with small cuvette and capillary filled with ethanol-water mixtures

Electrodynamic properties of quasi-optical dielectric resonators (QDRs) of two types with liquid-filled small cavities have been studied. Both eigen frequency and energy loss in the resonators depending on dimensions of the cavities are presented. One of the QDR types is a two-hemidisc resonator with a diametrical slot in which a cuvette with a thin (0.01- 0.1 mm) flat liquid layer is placed and the other is a disc resonator with a small diameter (0.3-2 mm) cylindrical capillary. Measurements have been carried out at room temperature in K a-waveband by using the resonators made of Teflon material. The obtained results allow to conclude that the given approaches to the development of measuring technique for characterization of liquids in small and with arbitrary loss tangent (for example, water and aqueous solutions) are quite perspective. Advantages and disadvantages of each resonator are considered briefly. The necessity to carry out both theoretical description of the electrodynamic properties of the QDR containing small liquid-filled cavities and determination of maximal sensitivity conditions for the measurement techniques is underlined. © 2007 Springer Science+Business Media, Inc.