Design and Demonstration of a RADAR Gauge for In-Situ Level Measurement in Furnace

A specially designed air-cooled compact antenna is proposed for non-contact real-time radio detection and ranging (RADAR)-level measurement in furnace. 3-D modeling is used to optimize the surface profile of the RADAR antenna for beam symmetry and low sidelobe level over 20-24 GHz. The fabricated RADAR sensor deployed in mono-static mode has 0.19-mm measurement error for a static target. Measurements in a closed furnace at 1100 degrees C demonstrate the feasibility of non-contact in-situ monitoring of the level of molten metal for long duration (11 hours) without degradation in the sensor performance.