Patent ID: 7589664

Claim:
A radar level gauge for measuring the level of a surface of a product stored in a container, said level gauge including: an antenna unit for transmitting microwave signals towards said surface and for receiving microwave signals reflected by said surface, a measuring and controlling unit for determining the level based on an evaluation of the time lapsed between the transmitted and the received signals, a radar module connected to said antenna unit, for generating microwave signals on at least two different frequency bands, said radar module including: a microwave generating source for providing a first microwave signal of a first frequency band having a first center frequency, at least one frequency multiplier coupled between said microwave generating source and said antenna unit for providing a second microwave signal of a second frequency band having a second center frequency, wherein the ratio between the second and the first center frequency is at least 1.5, and switches operated by means of a control signal for switching the radar module to operate on said first frequency band or said second frequency band, and a signal analyzer for analyzing the received signals on the frequencies transmitted by the antenna, and, based on analysis of the received signals, deciding on which frequencies the radar module will be operated, and generating said control signal.