Accession Number : ADP006120
Title : The Enhancement Effect of the Backscattering Intensity in a Ramdom Medium,
Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK COMMUNICATIONS AND SPACE SCIENCES LAB
Personal Author(s) : Yang, C. C.
Report Date : MAY 1987
Pagination or Media Count : 11
Abstract : A wave gradually loses its coherence while propagating in a random medium. This is because the wave experiences decorrelation along with propagation path that has uncorrelated irregularities. If, however, different parts of the propagation path have correlated irregularities, the decorrelation of the wave will not proceed as rapidly as otherwise. This effect is most prominently manifested in the case of backscattering where the returned wave propagates through the same irregularities as the outgoing wave. The average backscattered intensity can be shown to be higher than that expected from a wave propagating over a path equal to the round trip distance but through uncorrelated irregularities. This phenomenon is known as the enhancement effect. This enhancement effect is clearly revealed when the receiver is moved ever closer to the transmitter. As the separation between the receiver and the transmitter is reduced, the average scattered intensity will increase and reaches a peak when the receiver is co-located with the transmitter. As the separation between the receiver and the transmitter is reduced, the average scattered intensity will increase and reaches a peak when the receiver is co-located with the transmitter. If the wave statistics are in the saturation regime, this maximum increase amounts to a doubling of the average intensity. In this paper, the enhancement effect under various conditions is examined. There can be backscattering from random irregularities themselves or from a deterministic scattered. The differences between weak and strong scattering is distinguished. The effects produced by various power spectral functions from the random medium are also considered. (Author)
Descriptors : *ELECTROMAGNETIC WAVE PROPAGATION, *COHERENCE, SCATTERING, CORRELATION TECHNIQUES, POWER SPECTRA, BACKSCATTERING, SYMPOSIA.
Subject Categories : Radiofrequency Wave Propagation
Distribution Statement : APPROVED FOR PUBLIC RELEASE