The invention relates to a device, a probe, and a method for the galvanically decoupling transmission of a measuring signal. A microwave signal is supplied by a transceiver (1) to a sensor (3) by means of a galvanically decoupled waveguide (2). The signal is partially reflected in the sensor (3), the amplitude, phase and/or polarization of the reflected microwave signal containing the information relating to the measuring value. The reflected microwave signal runs through the same waveguide (2) back to the transceiver (1) and is evaluated therein. The invention provides a more simple and economical structure than conventional devices of prior art, as a voltage supply is not required especially on the sensor side as a result of the reflection. In this way, the sensor (3) can also be produced in a very compact manner, minimizing the influence of the measuring signal through the sensor (3).