Patent ID: 7345622

Claim:
A radar level gauge system for gauging the level of a filling material in a container, comprising: a waveguide extending towards the surface of said filling material; a transmitter for transmitting a microwave signal of a first mode of propagation in the waveguide; a receiver for receiving the microwave signal reflected against the surface of said filling material and propagating back through said waveguide; and processing circuitry for determining the filling level of the container based on said reflected microwave signal; and a transition element connecting the waveguide and the transmitter, wherein said transition element is configured to allow a part of the transmitted microwave signal to leak into a second mode of propagation; wherein said first and second modes of propagation are within a frequency band which admits propagation of said microwave signal in said two different modes of propagation in said waveguide, and wherein said receiver is arranged to receive said microwave signal in said at least two different modes of propagation.