Transient TE scattering from a cylinder above an infinite periodic surfaceusing a decomposition method

A cylindrical target above a periodic surface is illuminated by a short-pul se electromagnetic wave to study the effect of multipath on radar measureme nts of targets above the sea. A decomposition method is outlined for TE sca ttering from a cylinder above an infinite, periodic surface. The basis of t his method is that if a target is close to the sea, the current induced on the sea surface will be nearly identical to that induced by a plane wave wi thout the target present, except within a region of finite extent immediate ly beneath the target. A set of coupled Electric-Field Integral Equations ( EFIEs) for the current induced on the cylinder and the perturbation current (the difference between the current with the target present and with the t arget absent) on the surface has been derived in which the perturbation cur rent is approximated to zero outside a finite region beneath the cylinder. The EFIEs are solved in the frequency domain using the Method of Moments an d transformed into the time domain using the inverse Fourier transform. Use of this technique for studying the transient multipath phenomenon of a tar get located near a disturbed surface is discussed.