On the validity domain of a hybrid FDTD/UTD method for indoor channel modeling

Classical theories such as the uniform theory of diffraction (UTD) use analytical expressions for diffraction coefficients. These methods are widely used in radio communications to predict the channel behaviour. Indeed, they are very fast and applicable as long as the objects which interact during the wave propagation are canonical (dihedral for example) and much greater than the wavelength. For more complex and smaller scattering structures, rigorous methods as the finite difference time domain method (FDTD) is more suited. In this paper, we present an original approach, combining the advantages of these two complementary methods, in order to accurately characterise the propagation channel