Transient plane wave scattering from an annular ring above a lossy half space

Abstract

The transient backscattered field response of a ring above a lossy half space is investigated to gain a better understanding of the time-domain behavior of a radar target above the ocean or the earth's surface. The transition point from early to late time is determined for the three cases of the isolated ring, the ring above a lossless half space, and the ring above a lossy half space, using frequency inversion and SEM techniques. It is shown that when placed above a half space, the response of a target is a complicated succession of excitations, followed ultimately by a pure series of system natural modes. If the half space is lossy, the approximate effect on the late time is through the addition of two exponential signals with damping coefficients dependent on the incidence angle and the properties of the half space.