Diffraction over typical-shaped terrain obstacles

The attenuation by a curvilinear-topped obstacle and multiple flat-topped o bstacles are solved in the present paper based on Fresnel-Kirchhoff theory. The results have clear physical meaning and are simple to use, it only nee ds to change the signs of alpha(j) in Vogler's multiple knife-edge attenuat ion function to get each of the individual field, and add them up to get th e total field. Meanwhile, the attenuation by a wedge, a flat-topped obstacl e with bevel sides and double knife edges with ground reflection are also s olved by the attenuation formula of multiple knife edges with ground reflec tion given in the paper.