Diffraction Patterns at the Plane of a Slit in a Reflecting Screen

Abstract

Measurements were made of the diffraction pattern in slits ranging in width from 0.2 to 2.5 wavelengths. Microwave radiation of 10.4 and 16 cm was used. Ratios of intensity in the slit to the intensity of the unperturbed beam were found for plane polarized radiation incident on the conducting slit screen. Comparison with diffraction patterns in the plane of circular apertures was made. A peak of intensity was found for the slit width of one-half wavelength and a plateau was observed in the plot of intensity vs slit width in the region of width equal to one wavelength. A theory involving multiple reflections from the edges was utilized to explain the variations of intensity in the plane of the slit. The electric field was studied when polarized parallel and also perpendicular to the slit edges. A high intensity was found near the edges when the electric field was polarized perpendicular to them.