High-frequency radio wave diffraction from singly curved, convex surfaces a heuristic approach

An alternate approach is presented for the prediction of induced surface currents on perfect electric conducting (PEC) circular cylinders of large radius by observation of the asymptotic behaviour of the Fock currents. The currents are separated in the fashion of the physical theory of diffraction in terms of a uniform or physical optics component and a nonuniform or diffraction component which is highly localised to the shadow boundary. The approach can be extended to that of a general convex surface by application of known methods such as incremental-length diffraction coefficients. The case of the 2D PEC circular cylinder at normal incidence is developed first and then extended to that of oblique incidence analytically. The resulting expressions for the induced current are algebraic and are shown to be highly accurate for cylinders having radii of curvature larger than a wavelength. Total near-fields generated by this macromodelled current are in good agreement with those of the exact solution everywhere.