Three dimensional modeling of double diffraction phenomena by a high building

An efficient high frequency description of the double diffraction phenomena is of considerable practical importance in modeling of navigation, cellular radiotelephone and radio coverage in an urban area. The uniform theory of diffraction (UTD) has been extended to include double diffraction by a dielectric high building. The new double diffraction coefficient presented is relatively simple to apply since it is directly related to the product of two single diffraction coefficients. However the new diffraction coefficient needs to be extended to a dyadic formulation when the incident and diffracted rays are not perpendicular to the edge. The paper presents the theoretical approach and the effects of different parameters such as the frequency and the polarization when the receiver goes through the lit region, the shadow region and the deep shadow region. Measurements have been carried out at 10 GHz. The receiver is moving along the shadowed face of the building in each polarizations for several distances between the building and the receiver. A good agreement between the experimental results and the numerical analysis shows that the evolution of the received field can be predicted in the shadowed region with a good approximation