Accession Number:

ADA222908

Title:

Inlet Modeling Studies

Descriptive Note:

Technical rept.

Corporate Author:

OHIO STATE UNIV COLUMBUS ELECTROSCIENCE LAB

Report Date:

1986-10-01

Pagination or Media Count:

176.0

Abstract:

An analysis is developed for predicting the near zone fields scattered by perfectly-conducting, open-ended, semi-infinite circular and rectangular waveguides or ducts which are excited by an external electromagnetic EM plane wave. These waveguides are terminated inside by various structures such as a planar impedance surface, or a diskblade structure with and without a hemispherical or a conical hub. The analysis is based on a combination of asymptotic high frequency techniques such as ray methods, the equivalent current approach, and the physical theory of diffraction, with the usual modal techniques, all of which are used in conjunction with the multiple scattering method MSM. Basically, the scattering matrices in the MSM, which account for the multiple wave interactions between the open end and the interior termination are found efficiently via the asymptotic high frequency techniques. The latter techniques provide relatively simple expressions not only for the fields scattered from the rim edge at the open-end of the ducts, but also for the amplitudes of the modes coupled into the duct by the incident plane wave as well as the reflection coefficients of the modes at the open end. Some numerical results are provided for the near and far field bistatic scattering. RH

Subject Categories:

  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE