Slope diffraction analysis of TEM parallel-plate guide radiation patterns

The radiation pattern of the transverse electromagnetic- (TEM) mode parallel-plate waveguide is analyzed by the wedge-diffraction theory in conjunction with a slope-correction term. This term takes into account the nonuniform wave in the analysis of second-order diffractions for an open-ended guide. This slope-correction term provides improved accuracy of the pattern in the region near the plane of the aperture when compared to the usual wedge-diffraction method.