Characteristics of Diffracted Waves Going over Building Rooftop

In order to have an effective utilization of the radio wave resources, it is important to estimate propagation path in the urban area. In our previous work, we have examined the diffracted fields by two edges with an arbitrary angle which are in different and same heights. In this paper, the characteristics of the diffracted fields by two horizontal edges of a building rooftop are discussed. The numerical calculations are carried out for two wedges of a building rooftop on perfect conductor and concrete wedges. The results show that the waves grazing on the rooftop of concrete building are considerably attenuated for the low concrete conductivity, but when parapets are constructed on the rooftop, the diffracted waves become stronger than the grazing waves.