Obstacle Based Concept for Compact Mode-Preserving Waveguide Transitions for High-Precision Radar Level Measurements

Gunnar Armbrecht, Eckhard Denicke, Nils Pohl, Thomas Musch, Ilona Rolfes

38th European Microwave Conference (EuMC), pp. 472-475 , Amsterdam, The Netherlands, Oct 28-30, 2008


This contribution deals with a concept for the realization of compact mode-preserving waveguide transitions. For radar distance measurements, the cross-section of a single-moded waveguide is enlarged to an overmoded circular waveguide. In order to obtain a mostly monomode signal propagation within the waveguide, a parabolic waveguide transition in combination with a centrically mounted metallic obstacle is investigated. In comparison to the same transition without obstacle, a significant improvement in terms of the fundamental H11 mode preservation can be achieved over a wide frequency range from 8.5 to 10.5 GHz. Radar measurements are presented that prove the capability of such a concept providing submillimeter distance accuracy without any need of modifying the applied conventional free-space signal processing algorithms.

[IEEE Library]

Tags: distance, Measurements, radar