Measuring device for measuring change in the dielectric properties in an environment, comprising - a capacitive measuring circuit provided with an input and output electrical connection (20;21), wherein the measuring circuit comprises one or more coupled measuring capacitors (5;50) which are placeable in the environment and wherein the capacitance of each of the measuring capacitors (5;50) can be influenced by the dielectric properties of the environment, - an electric alternating signal generator connected a common ground for applying a first electric alternating signal with a specific base frequency and a specific signal shape to the input connection of the measuring circuit wherein the input connection and output connection are indirectly connected to the common ground connection, - a first signal processing means for deriving a second electric alternating signal from the first signal, wherein the second signal has the same base frequency and signal shape as the first signal and is shifted 90° in phase relative to the first signal, - first quadrature determining means for calculating the in-phase component I1 C and quadrature component Q1c of an output voltage Uc across the output connection of the measuring circuit, wherein the first signal and second signal function as reference signals, characterized in that the measuring device is provided with - second quadrature determining means for calculating the in-phase component I1 L and quadrature component Q1 L of an input voltage U L across the input connection of the measuring circuit, wherein the first signal and second signal function as reference signals, - a calculation circuit configured to calculate a ratio of the in-phase components (I1 L, I1 C) and quadrature components (Q1 L, Q1 C) of the output voltage (U L) and input voltage (U C). - a capacitive measuring circuit provided with an input and output electrical connection (20;21), wherein the measuring circuit comprises one or more coupled measuring capacitors (5;50) which are placeable in the environment and wherein the capacitance of each of the measuring capacitors (5;50) can be influenced by the dielectric properties of the environment, - an electric alternating signal generator connected a common ground for applying a first electric alternating signal with a specific base frequency and a specific signal shape to the input connection of the measuring circuit wherein the input connection and output connection are indirectly connected to the common ground connection, - a first signal processing means for deriving a second electric alternating signal from the first signal, wherein the second signal has the same base frequency and signal shape as the first signal and is shifted 90° in phase relative to the first signal, - first quadrature determining means for calculating the in-phase component I1 C and quadrature component Q1c of an output voltage Uc across the output connection of the measuring circuit, wherein the first signal and second signal function as reference signals, characterized in that the measuring device is provided with - second quadrature determining means for calculating the in-phase component I1 L and quadrature component Q1 L of an input voltage U L across the input connection of the measuring circuit, wherein the first signal and second signal function as reference signals, - a calculation circuit configured to calculate a ratio of the in-phase components (I1 L, I1 C) and quadrature components (Q1 L, Q1 C) of the output voltage (U L) and input voltage (U C).