The Second-Order High Frequency Radar Ocean Surface Foot-Scatter Cross Section for an Antenna on a Floating Platform

Abstract

While the first-order and a portion of the second-order scattering mechanism for high frequency surface wave radar signals from the ocean surface for the case of the antennas being mounted on a floating platform have been addressed earlier, here the case of one of two scatters occurring near the transmitting and/or receiving antenna is considered. The relevant fields, reduced to monostatic form for the case of a pulsed dipole source and a time-invariant rough surface, are extended to include the ocean surface, which is considered to be a zero-mean Gaussian process. The new contributions to the radar cross section (RCS) again appear as Bessel functions, which give rise to additional features in the overall RCS. The effects are generally much smaller than those associated with the first-order scattering except at specific frequencies in the spectral regions beyond the peaks of the usual second-order energy and also near zero Doppler.