Correction to "Application Of Incremental Length Diffraction Coefficients To Calculate The Pattern Effects Of The Rim And Surface Cracks Of A Reflector Antenna"

TLDR: In this article, the effect of cracks on the surface of reflectors that can result from the imperfect fitting together of panels to form large reflectors was investigated. But the results were limited to three models of cracks, and significant pattern effects were found, depending on the model and orientation of the cracks.

Abstract: Incremental length diffraction coefficients (ILDCs) for the half-plane are integrated around the rim of a paraboloid reflector antenna to obtain well-behaved far fields of the nonuniform current for all angles of observation. These far fields, when added to the physical optics far field, produce a more accurate total far field of the reflector. Excellent agreement with the far fields obtained from a method-of-moments solution to the electric field integral equation applied to a 20-wavelength-diameter reflector shows that the cross polarization, farther-out sidelobes, and fields near nulls of reflector antennas can be appreciably modified by the fields of the nonuniform currents. ILDCs are also used to investigate the effect of cracks on the surface of reflectors that can result from the imperfect fitting together of panels to form large reflectors. Three models of cracks are studied. Significant pattern effects are found, depending on the model and orientation of the cracks. >