A method for determining a dielectric value of a medium via a measuring device, the method comprising:
- providing the measuring device, including:
- a signal production unit designed to produce an electrical, high frequency signal having a frequency varying within a frequency band;
- a first waveguide having an in-coupling element designed to couple the produced high frequency signal into the first waveguide, a first end region designed for reflecting the high frequency signal, and a first signal gate arranged lying opposite the first end region via which the high frequency signal can be out-coupled into the medium;
- a second waveguide having a second end region is designed for reflecting the high frequency signal, a second signal gate arranged lying opposite the second end region and arranged lying opposite the first signal gate such that the high frequency signal is in-coupleable into the second waveguide via the second signal gate after passage through the medium, and an out-coupling element designed to out-couple the high frequency signal from the second waveguide;
- an electrically conductive arrangement that electrically contacts the two waveguides with one another;
- and
- a signal evaluation unit connected at least to the out-coupling element, wherein the signal evaluation unit is configured:
- to receive within the frequency band a frequency-dependent, reflected fraction of the high frequency signal in-coupled into the first waveguide and/or a frequency-dependent, transmitted fraction of the high frequency signal in-coupled into the first waveguide,
- to ascertain, based on the reflected fraction, a frequency-dependent, reflection minimum and a corresponding frequency, and/or to ascertain, based on the transmitted fraction, a frequency-dependent, transmitted maximum and a corresponding frequency,
- to determine, based on the corresponding frequency of the reflection minimum or based on the corresponding frequency of the transmitted maximum, a real part of the dielectric value,
- to determine, based on the transmitted fraction at the corresponding frequency of the reflection minimum, an imaginary part of the dielectric value, and
- to determine, based on the imaginary part of the dielectric value and the real part of the dielectric value, a magnitude of the dielectric value;
- producing the electrical, high frequency signal via the signal production unit;
- in-coupling the high frequency signal via the in-coupling element into the first waveguide;
- out-coupling the high frequency signal from the second waveguide via the out-coupling element after passage through the medium;
- recording the frequency-dependent, reflected fraction and the frequency-dependent, transmitted fraction of the in-coupled high frequency signal;
- ascertaining the frequency-dependent, reflection minimum and the corresponding frequency of the high frequency signal, and/or ascertaining the frequency-dependent, transmitted maximum and the corresponding frequency of the high frequency signal;
- determining the real part of the dielectric value based on the frequency of the reflection minimum or based on the frequency of the transmitted maximum;
- and
- determining the imaginary part of the dielectric value based on the transmitted fraction at the frequency of the reflection minimum or at the frequency of the transmitted maximum.