scholarly journals Compact mode-matched excitation structures for radar distance measurements in overmoded circular waveguides

2008 ◽  
Vol 6 ◽  
pp. 9-17 ◽  
Author(s):  
G. Armbrecht ◽  
E. Denicke ◽  
I. Rolfes ◽  
N. Pohl ◽  
T. Musch ◽  
...  
Keyword(s):  
Circular Waveguide ◽  
Design Criterion ◽  
Distance Measurements ◽  
Mode Suppression ◽  
Spurious Mode ◽  
Propagation Effects ◽  
Circular Waveguides ◽  
Radar Measurements ◽  
Waveguide Transitions ◽  
Waveguide Taper

Abstract. This contribution deals with guided radar level measurements of liquid materials in large metal tubes, so-called stilling wells, bypass or still pipes. In the RF domain these tubes function as overmoded circular waveguides and mode-matched excitation structures like waveguide tapers are needed to avoid higher order waveguide modes. Especially for high-precision radar measurements the multimode propagation effects need to be minimized to achieve submillimeter accuracy. Therefore, a still pipe simulator is introduced with the purpose to fundamentally analyze the modal effects. Furthermore, a generalized design criterion is derived for the spurious mode suppression of compact circular waveguide transitions under the constraint of specified accuracy levels. According to the obtained results, a promising waveguide taper concept will finally be presented.

scholarly journals Radar distance measurements in circular waveguides involving intermodal dispersion effects

2010 ◽  
Vol 2 (3-4) ◽  
pp. 409-417 ◽  
Author(s):  
Eckhard Denicke ◽  
Gunnar Armbrecht ◽  
Ilona Rolfes
Keyword(s):  
Measurement Precision ◽  
Level Control ◽  
Distance Measurements ◽  
Dispersion Effects ◽  
Waveguide Transition ◽  
Measurement Results ◽  
Intermodal Dispersion ◽  
Circular Waveguides ◽  
Signal Complexity ◽  
Waveguide Transitions

This contribution deals with guided radar distance measurements in the field of industrial tank level control. The aim is to achieve a submillimeter gauging accuracy even when conducting the measurement within a highly dispersive environment of large and thus overmoded circular waveguides. Normally, multimode propagation causes a decrease in measurement precision. Therefore, the effects of intermodal dispersion are fundamentally reviewed and, based on these results, a correlation-based signal processing method is presented. This method is able to exploit the otherwise parasitic dispersion effects to enhance the measurement precision even in constellation with a simple waveguide transition or antenna, respectively. Furthermore, considerations on the mode variety and its influence on the signal complexity as well as investigations on the technique's reliability and accuracy are presented. Measurement results in a frequency range of 8.5–10.5 GHz are provided for three different kinds of waveguide transitions proving the capability of the method.

Rigorous study of propagation in metallic circular waveguide filled with anisotropic metamaterial

2017 ◽  
Vol 9 (4) ◽  
pp. 805-813 ◽  
Author(s):  
Hedi Sakli ◽  
Mohamed Yahia ◽  
Wyssem Fathallah ◽  
Jun Wu Tao ◽  
Taoufik Aguili
Keyword(s):  
Computation Time ◽  
Circular Waveguide ◽  
Transverse Magnetic ◽  
Higher Order Modes ◽  
Anisotropic Metamaterials ◽  
Matching Technique ◽  
Theoretical Predictions ◽  
Rigorous Study ◽  
Circular Waveguides ◽  
Anisotropic Metamaterial

This paper presents an extension of the formulation of wave propagation in transverse electric (TE) and transverse magnetic (TM) modes in the case of metallic circular waveguides filled with anisotropic metamaterials. The determined higher-order modes have been analyzed and exploited to the design of filters. Among the particularities of anisotropic material, the backward waves can propagate below the cut-off frequency. The numerical results for TE and TM modes have been compared with theoretical predictions. Good agreements were obtained. We analyzed a periodic structure containing waveguides filled with anisotropic metamaterial using the mode-matching technique. By using modal analysis, our approach reduced considerably the computation time compared to HFSS.

High Precision Radar Distance Measurements in Overmoded Circular Waveguides

2007 ◽  
Vol 55 (6) ◽  
pp. 1374-1381 ◽  
Author(s):  
Nils Pohl ◽  
Michael Gerding ◽  
Bianca Will ◽  
Thomas Musch ◽  
Josef Hausner ◽  
...  
Keyword(s):  
High Precision ◽  
Distance Measurements ◽  
Circular Waveguides

Radar Distance Measurements in Over-sized Circular Waveguides

2006 ◽  
Author(s):  
T. Musch ◽  
N. Pohl ◽  
M. Gerding ◽  
B. Will ◽  
J. Hausner ◽  
...  
Keyword(s):  
Distance Measurements ◽  
Circular Waveguides
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