Abstract
A new method for determining electrodynamic characteristics of the fluids contained in isolated plastic vessels (the bottles) is suggested. Main concept of the method is in using the interaction between the surface electromagnetic wave of the dielectric waveguide and the cylindrical vessel filled with the liquid. At propagation of the electromagnetic wave within a structure like that, variation of the signal amplitude is observed at the output of the dielectric waveguide. At the assumption that the thickness of the standard cylindrical shell of the vessel is negligibly small as compared to the operation wavelength, the varied signal characteristics are determined primarily by the electric characteristics of the liquid. The above idea formed the basis of the method allowing development of the detector capable of distinguishing well one liquid from the other.