Patent ID: 8018373
Filing Date: 2011-09-13
Classification: G01F,G01S,H01Q

Abstract:
1. A radar level gauge system using microwaves for measuring a level of a surface of a product in a container, comprising: a transceiver for generating, transmitting and receiving electromagnetic signals within a frequency range, a waveguide arranged to extend into said product contained in the container and to guide signals transmitted from said transceiver towards a surface of said product and to guide echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals, including surface echo signals resulting from reflection at said surface, back to said transceiver, processing circuitry connected to the transceiver and arranged to determine the level of the surface based on a relation between the transmitted and received electromagnetic signals, an interface for providing communication externally of said system and for receiving power to the radar level gauge system, and a plurality of reference impedance transitions being arranged at known positions along the waveguide and being configured to reflect a portion of said transmitted electromagnetic signals back towards said transceiver, wherein each of said reference impedance transitions has a first reflection coefficient for said electromagnetic signals when the level of the surface is above the reference impedance transition and a second reflection coefficient for said electromagnetic signal when the level of the surface is below the reference impedance transition, said first reflection coefficient being substantially lower than said second reflection coefficient.