A new UTD formulation for multiple cylindrical diffraction
This paper describes a new formulation of the uniform theory of diffraction (UTD) with application to multiple cylindrical structures. The new formulas present some modified UTD diffraction coefficients in cooperation with a slope diffraction term for higher accuracy in the electromagnetic modeling. The above are then combined with a simple ray tracing algorithm that takes into account multipath propagation between cylindrical structures. Comparisons with existing analytical models that employ other electromagnetic theories have shown that the new UTD solution can give very accurate results while it seems to be superior in terms of computation time and complexity. The solution can be applicable to radiowave paths which are characterized by convex structures and multipath propagation such as mountainous areas or urban areas with special rounded objects
An improved heuristic UTD solution for multiple-edge transition zone diffraction
This paper describes a new heuristic approach for multiple edge diffraction modeling based on the uniform theory of diffraction (UTD). It incorporates the slope diffraction terms which can be realized as a second-order diffraction process, vital for accurate predictions when more than one edge exists. The predictions of this approach are compared with the Vogler (1982) solution and were found to be in very good agreement for many different geometrical arrangements, with low computational complexity. The solution is also extended to wedge diffraction.
Comments on "A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface"
The edge diffraction coefficients of Kouyoumjian and Pathak, when applied to edges in curved screens produce discontinuities in the diffracted fields which do not coincide with those of the specular field on the concave side of the screen. In regions where coincidence occurs the discontinuities add, rather than cancel. The field calculated from the diffraction coefficient violates the principle of reciprocity.