Improved heuristic diffraction coefficients for an impedance wedge at normal incidence

A method to extend the range of validity of heuristic diffraction coefficients for an impedance wedge to all diffraction and incidence angles is suggested. The proposed diffraction coefficients enforce continuity of the total field, are reciprocal and symmetrical, and satisfy plausible boundary conditions on the wedge faces. Good agreement with Maliuzhinets´ method is observed in all conditions, excluding those for which the first-order impedance boundary conditions are known to be inaccurate.