Radiating impedance end face of rectangular waveguide

The approximate analytical solution of the problem of the basic wave-mode diffraction on the narrow slot what is cut in the impedance end face wall of the finite thickness have been obtained by the induced magnetomotive forces method. It is proposed that waveguide is half-infinite and the slot radiates into the free space over the infinite ideally conducting screen. The scattering matrix coefficients were numerically investigated in the case when values of the complex surface impedance correspond to some concrete realization of the film coating of the waveguide end face wall.