Guided Microwave Level Transmitters, this type of level transmitter works by sending a microwave or electromagnetic pulse through a sensor rod/cable. When the signal hits the surface of the liquid, it travels back up the sensor rod and back to the transmitter housing.
The electronics are integrated into the transmitter housing, which determine the filling level from the time taken for the signal to travel down the sensor rod and back up again. The value is then shown in the display of the transmitter. This type of level transmitter is suitable for liquids, and is used in industrial applications in all areas of process technology.