AN Improved UTD Based Model For the Multiple ‎Building Diffraction of Plane Waves in Urban ‎Environments By Using Higher Order Diffraction ‎Coeficients

This paper describes an improved model for multiple building diffraction modeling based on the uniform ‎theory of diffraction (utd). a well-known problem in conventional uniform theory of diffraction (cutd) ‎is multiple-edge transition zone diffraction. here, higher order diffracted fields are used in order to improve ‎the result; hence, we use higher order diffraction coefficients to improve a hybrid physical optics (po)-‎cutd model, the results show that the new model corrects errors of the po-cutd model. therefore, the ‎proposed model can find application in the development of theoretical models to predict more realistic path ‎loss in urban environments when multiple-building diffraction is considered.‎