MULTIPLE DIFFRACTION OF ELECTROMAGNETIC WAVES BY A WEDGE OF CONCAVE SHAPE

Multiple diffraction of short-wavelength electromagnetic waves by a wedge of concave shape is analysed with the uniform geometrical theory of diffraction (UTD). The resulting wave field is a superposition of a variety of edge-diffracted and specularly reflected waves, treated as “channels of multiple diffraction”. The algorithms of UTD allow of describing birth and disappearance of diffraction channels under evolution of the wedge shape. Classification of diffraction channels is suggested and dominant channels are selected. The “four/five channels model ” of scattering is proposed, which describes effectively diffraction of electromagnetic waves by steep and breaking water waves of mesoscale spectrum and embraces the main interference and polarization phenomena, characteristic of low-grazing angles of radar sounding, including enhanced backscattering, suppression of vertically polarized echoes due to Brewster effect and “super events”—gigantic spikes of radar cross-section (RCS). It is shown that RCS for plain individual mesowave of 30 cm height and of 1 m front width may reach as large value as 1-10 m