High-frequency bistatic cross sections of the ocean surface

An analysis leading to the first- and second-order bistatic cross sections of the ocean surface in the context of high-frequency ground wave radar operation is presented. Initially, a pulsed dipole source is introduced into the previously derived electric field expressions for the bistatic reception of vertically polarized radiation scattered from rough surfaces that do not vary with time. To make application to the ocean, a time-varying surface is introduced via a three-dimensional Fourier series with two spatial variables and one temporal variable. The surface randomness is accounted for by allowing the Fourier coefficients to be zero-mean Gaussian random variables. Fourier transformation of the autocorrelations of the resulting fields gives the appropriate power spectral densities. The latter are used in the bistatic radar range equation to produce the cross sections. The features of the bistatic case are seen to reduce to the well-known monostatic results when the appropriate geometry is introduced. Illustrative comparisons of monostatic and bistatic reception are presented.