A method for computing -plane patterns of horn antennas

This paper introduces a method for calculating the total antenna pattern in the plane, including the backlobe region, of a horn by applying diffraction theory. Treatment of diffraction by a thick edge permits horns of various edge thicknesses to be treated. The diffraction concepts developed by Sommerfeld and Pauli, which treated plane wave diffraction by a wedge, are extended so that diffraction of plane and cylindrical waves by thin or thick edges may be treated. The diffracted fields are obtained by applying the relations developed by Pauli in conjunction with reciprocity. When the theory is applied to the horn, the significant radiation mechanisms are direct radiation from the source at the horn apex and diffracted radiation due to the edges. The computed -plane patterns of a horn antenna agree with measured patterns.