Time-domain analysis of multiple scattering effects on the radar cross section (RCS) of objects in a random medium

This paper presents a theory of the time-domain radar cross section (RCS) of objects in discrete random media. The time-domain formula is obtained by applying the inverse Fourier transform of the two-frequency mutual coherence function (MCF) which is derived from both the second-order Rytov approximation and the strong fluctuation theory. This theory includes the backscattering enhancement and the time-domain shower curtain effect that are not normally considered in the conventional theory. Numerical examples of the time-domain RCS of a conducting square plate in a discrete random medium characterized by the Gaussian phase function are shown to highlight the random media effects on the time-domain waveforms including time delay and pulse broadening in terms of optical depth and random medium location. Numerical results show that both pulse arrival time and pulse broadening increase significantly when the random media is placed far from the target. This degradation of the image quality, known as the shower curtain effect, can be explained by the characteristics of the incoherent component.