Millimeterwave Radar Systems for in-line Thickness Monitoring in Pipe Extrusion Production Lines

Jochen Jebramcik, Ilona Rolfes, Nils Pohl, Jan Barowski

IEEE Sensors Letters, Vol.​ 4, Issue: 5, doi: 10.1109/LSENS.2020.2991778, May 2020


This letter presents algorithms and considerations for the applicability of millimeter wave radar systems as monitoring sensors in the field of plastic pipe extrusion. Since a constant wall thickness of the pipe is a major quality factor of the product, monitoring systems that in-line measure the thickness during the extrusion process are commonly used. Modern ultrawideband radar systems achieve target resolutions in the range of millimeters, allowing competition with well-established methods, such as ultrasound sensors, and even expensive photonic Terahertz devices. The authors describe a novel accurate and efficient method to measure the pipe-wall's thickness based on frequency domain evaluation of the material reflection. The general feasibility of W-band radar sensors, as well as the accuracy of the proposed method, is demonstrated by measurements using a moderate size polyvinyl chloride pipe.