Importance of the Fresnel Correction in Scattering from a Rough Surface. I. Phase and Amplitude Fluctuations

Abstract

Three rough surfaces 32 in. by 32 in. in size were made of a pressure-release material. The amplitude and phase of a pulsed wave scattered in the specular direction were measured at a frequency of 95.8 kHz for grazing angles from 6° to 80°. The theoretical approach of Gulin was used successfully in the Fresnel approximation to predict the observed amplitude and phase fluctuations for a Rayleigh parameter less than 0.6. Experimental measurements were extended to a Rayleigh parameter of 7.4. The observed fluctuations in the amplitude reached saturation at a Rayleigh parameter of 2.0 and fluctuated about this maximum as the parameter increased to 7.4. The fluctuations in the phase increased with the Rayleigh parameter, but there is some evidence that the phase fluctuation, like the amplitude fluctuations, saturates.