Electromagnetic Scattering by Open Circular Waveguides.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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Open circular waveguides are used to model jet engine inlets. The exact Wiener-Hopf solution for scattering by a semi-infinite cylinder is studied in the resonance region, where the cylinder diameter is of the order of a wavelength. In particular, the Wiener-Hopf factorization functions are calculated by numerical integration and compared to various approximations, to define regions of validity. Scattering from the rim is studied as a function of frequency, incidence angle, and time. A ray-optic model for rim backscatter is discussed. The relative power absorption of the five lowest order waveguide modes is evaluated. Coupling of incident plane waves to waveguide modes, and radiation by these modes are shown to be related by reciprocity. The waveguide termination model for a jet engine assumes an incident waveguide mode strikes an axially symmetric cone on a flat plate. The various techniques for evaluating scattering by this structure are discussed, and the problem is solved for a few cases. Author
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation
- Jet and Gas Turbine Engines