Extremely short microwave pulses are transmitted via the antenna system, to the material to be measured, the pulses are reflected by the surface of the material, and received back to the antenna system.
The time taken between the transmission of the pulses and receiving the pulses,
is proportional to the level in the vessel.
Because the pulses are travelling so fast, and difficult to process, a procedure is adopted to allow for the processing of the pulses. The pulses are transmitted in the K-band frequency range, where its usage is time proven.
The transmitted power is well below the IEC specifications. There is no need to calibrate the vessel whether empty or full.