a single position without having to change this position of the container with respect to the resonator arrangement fig3 shows an arrangement according to the invention for use of the resonator arrangement with a dual mode resonator for identifying a fluid in a closed container the bottle is placed laterally and as centrally as is possible onto a retaining plate of the resonator the best coaxial mode coupling to the fluid is achieved if the axis of the bottle is disposed parallel to the shorting bar 17 in fig1 using the two network analyzers nwa 1 and nwa 2 the changes in quality and resonant frequency caused by the particular bottle in the two modes are measured in order to analyze the dielectric constant by way of the dielectric resonator the ratio of the change in the resonant frequency to the change in the reciprocal quality is preferably used for the conductivity measurements the change in the reciprocal quality of the coaxial mode caused by the bottle can be used using the arrangement from the example regular tap water can be clearly differentiated from distilled water applications of the device according to the invention relate to use for the detection of samples in closed containers and for the detection of water fat and salt content or acid content in tissues and other samples such as medical samples tissue and the like it is expressly noted that the arrangement r shown in fig1 is already fully functional without the dielectric resonator it is further pointed out that any resonator arrangement can solve the problem of the invention which comprises an lc oscillator circuit and a dielectric resonator wherein the mode of the.