The Experts below are selected from a list of 9036 Experts worldwide ranked by ideXlab platform

Burkhard Schiek - One of the best experts on this subject based on the ideXlab platform.

  • compact mode matched excitation structures for radar distance measurements in overmoded Circular Waveguides
    Advances in Radio Science, 2008
    Co-Authors: Gunnar Armbrecht, Nils Pohl, Thomas Musch, Eckhard Denicke, Ilona Rolfes, Burkhard Schiek
    Abstract:

    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.

  • Radar distance measurements in over-sized Circular Waveguides
    Proceedings of the 36th European Microwave Conference, EuMC 2006, 2007
    Co-Authors: Thomas Musch, Bianca Will, Josef Hausner, Nils Pohl, Michael Gerding, Burkhard Schiek
    Abstract:

    One of the main tasks of industrial radar systems is the determination of distances to a reflecting object. An important application is the measurement in metal tubes e.g. by means of the FMCW method. A comparison of measurements in metal tubes and in free-space shows that several problems arise due to the non-perfect coupling between the feeding antenna and the metal tube. This contribution describes the problems caused by dispersions and multi-mode propagations, and presents approaches for their solution

  • High Precision Radar Distance Measurements in Overmoded Circular Waveguides
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Nils Pohl, Bianca Will, Josef Hausner, Michael Gerding, Thomas Musch, Burkhard Schiek
    Abstract:

    Distance measurements in overmoded Waveguides are an important application for industrial radar systems. The accuracy of the measurements is deteriorated by the appearance of higher order modes in the metal tube, although the frequency-modulated continuous-wave method is used with a large bandwidth. This paper describes the problems caused by dispersion and multimode propagation and presents a solution in the form of mode-matched antennas for feeding the overmoded waveguide. It is shown that different modes, e.g., the H11 and H01 modes, are equally well suited for precision distance measurements, as is demonstrated both by simulations and measurements.

R. Vahldieck - One of the best experts on this subject based on the ideXlab platform.

  • analysis of propagation in periodically loaded Circular Waveguides
    IEE Proceedings - Microwaves Antennas and Propagation, 1999
    Co-Authors: Smain Amari, R. Vahldieck, J Bornemann
    Abstract:

    A technique is presented for the analysis of propagation in a Circular waveguide periodically loaded with irises of finite thickness. The propagation constants of the Floquet modes are determined from the classical eigenvalues of a characteristic matrix instead of a nonlinear determinant equation. Numerical results are presented for the TE/sub 0n/ modes and compared with available data. Excellent agreement is documented.

  • analysis of ridged Circular Waveguides by the coupled integral equations technique
    IEEE Transactions on Microwave Theory and Techniques, 1998
    Co-Authors: S. Amari, R. Vahldieck, S Catreux, J Bornemann
    Abstract:

    Cutoff wavenumbers of transverse electric (TE) and transverse magnetic (TM) modes of ridged Circular Waveguides are accurately determined using the coupled-integral-equations technique (CIET). A set of coupled integral equations for the electric field at the interfaces are derived and then solved by the moment method. Basis functions which include the edge conditions at all metallic edges are used. Results from this paper are compared with available data to demonstrate the accuracy and efficiency of the approach.

  • Radial mode matching analysis of ridged Circular Waveguides
    IEEE Transactions on Microwave Theory and Techniques, 1996
    Co-Authors: U. Balaji, R. Vahldieck
    Abstract:

    In this paper a radial mode matching analysis is presented to calculate rigorously the TE and TM mode propagation in single- double-, triple-, and quadruple-ridged Circular waveguide structures. The ridges have been cut radially in all the cases. Results are presented for variations of the ridge depth and ridge thickness and are compared to results from finite element analysis. Furthermore, for the first time, the characteristic impedance of the double and quadruple-ridged Circular Waveguides have been calculated using the power-voltage definition.

Nils Pohl - One of the best experts on this subject based on the ideXlab platform.

  • compact mode matched excitation structures for radar distance measurements in overmoded Circular Waveguides
    Advances in Radio Science, 2008
    Co-Authors: Gunnar Armbrecht, Nils Pohl, Thomas Musch, Eckhard Denicke, Ilona Rolfes, Burkhard Schiek
    Abstract:

    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.

  • Radar distance measurements in over-sized Circular Waveguides
    Proceedings of the 36th European Microwave Conference, EuMC 2006, 2007
    Co-Authors: Thomas Musch, Bianca Will, Josef Hausner, Nils Pohl, Michael Gerding, Burkhard Schiek
    Abstract:

    One of the main tasks of industrial radar systems is the determination of distances to a reflecting object. An important application is the measurement in metal tubes e.g. by means of the FMCW method. A comparison of measurements in metal tubes and in free-space shows that several problems arise due to the non-perfect coupling between the feeding antenna and the metal tube. This contribution describes the problems caused by dispersions and multi-mode propagations, and presents approaches for their solution

  • High Precision Radar Distance Measurements in Overmoded Circular Waveguides
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Nils Pohl, Bianca Will, Josef Hausner, Michael Gerding, Thomas Musch, Burkhard Schiek
    Abstract:

    Distance measurements in overmoded Waveguides are an important application for industrial radar systems. The accuracy of the measurements is deteriorated by the appearance of higher order modes in the metal tube, although the frequency-modulated continuous-wave method is used with a large bandwidth. This paper describes the problems caused by dispersion and multimode propagation and presents a solution in the form of mode-matched antennas for feeding the overmoded waveguide. It is shown that different modes, e.g., the H11 and H01 modes, are equally well suited for precision distance measurements, as is demonstrated both by simulations and measurements.

Thomas Musch - One of the best experts on this subject based on the ideXlab platform.

  • compact mode matched excitation structures for radar distance measurements in overmoded Circular Waveguides
    Advances in Radio Science, 2008
    Co-Authors: Gunnar Armbrecht, Nils Pohl, Thomas Musch, Eckhard Denicke, Ilona Rolfes, Burkhard Schiek
    Abstract:

    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.

  • Radar distance measurements in over-sized Circular Waveguides
    Proceedings of the 36th European Microwave Conference, EuMC 2006, 2007
    Co-Authors: Thomas Musch, Bianca Will, Josef Hausner, Nils Pohl, Michael Gerding, Burkhard Schiek
    Abstract:

    One of the main tasks of industrial radar systems is the determination of distances to a reflecting object. An important application is the measurement in metal tubes e.g. by means of the FMCW method. A comparison of measurements in metal tubes and in free-space shows that several problems arise due to the non-perfect coupling between the feeding antenna and the metal tube. This contribution describes the problems caused by dispersions and multi-mode propagations, and presents approaches for their solution

  • High Precision Radar Distance Measurements in Overmoded Circular Waveguides
    IEEE Transactions on Microwave Theory and Techniques, 2007
    Co-Authors: Nils Pohl, Bianca Will, Josef Hausner, Michael Gerding, Thomas Musch, Burkhard Schiek
    Abstract:

    Distance measurements in overmoded Waveguides are an important application for industrial radar systems. The accuracy of the measurements is deteriorated by the appearance of higher order modes in the metal tube, although the frequency-modulated continuous-wave method is used with a large bandwidth. This paper describes the problems caused by dispersion and multimode propagation and presents a solution in the form of mode-matched antennas for feeding the overmoded waveguide. It is shown that different modes, e.g., the H11 and H01 modes, are equally well suited for precision distance measurements, as is demonstrated both by simulations and measurements.

J Bornemann - One of the best experts on this subject based on the ideXlab platform.

  • analysis of propagation in periodically loaded Circular Waveguides
    IEE Proceedings - Microwaves Antennas and Propagation, 1999
    Co-Authors: Smain Amari, R. Vahldieck, J Bornemann
    Abstract:

    A technique is presented for the analysis of propagation in a Circular waveguide periodically loaded with irises of finite thickness. The propagation constants of the Floquet modes are determined from the classical eigenvalues of a characteristic matrix instead of a nonlinear determinant equation. Numerical results are presented for the TE/sub 0n/ modes and compared with available data. Excellent agreement is documented.

  • analysis of ridged Circular Waveguides by the coupled integral equations technique
    IEEE Transactions on Microwave Theory and Techniques, 1998
    Co-Authors: S. Amari, R. Vahldieck, S Catreux, J Bornemann
    Abstract:

    Cutoff wavenumbers of transverse electric (TE) and transverse magnetic (TM) modes of ridged Circular Waveguides are accurately determined using the coupled-integral-equations technique (CIET). A set of coupled integral equations for the electric field at the interfaces are derived and then solved by the moment method. Basis functions which include the edge conditions at all metallic edges are used. Results from this paper are compared with available data to demonstrate the accuracy and efficiency of the approach.