Electromagnetic scattering by open circular waveguides


  • Thomas W. Johnson,

  • D. L. Moffatt


The calculation of the radar scattering characteristics of open circular waveguides is approached by the Wiener-Hopf technique. The Wiener-Hopf factorization functions are calculated by numerical integration, and these results are compared to dc and high-frequency asymptotic approximations. The exact Wiener-Hopf solutions for scattering, coupling, and reradiation by semi-infinite circular waveguides are then computed for representative cases including axial backscatter with no internal obstacles, and backscatter based on the coupling to and radiation from individual waveguide modes. Finally, the high-frequency asymptotic solution for axial backscatter is transformed into the time domain and compared to the result of numerical transformation of the backscatter results obtained from numerical integration.