Hybrid technique combining the backward ray tracing and the FDTD method

In this contribution, possibility of using the backward ray tracing (RT) coupled with the finite-difference timedomain (FDTD) method for two-dimensional (2-D) simulations of the wave propagation in urban environments is demonstrated. For increased accuracy of exposure-assessment simulations, the FDTD method is used in small domains including inhomogeneous scatterers, whereas RT is used to simulate the wave propagation between these domains and buildings in urban environment. In this approach, contrary to the forward RT, many rays are generated for each diffracted ray and contributions from each receiver-transmitter path finally provide an excitation for the FDTD domains. A heuristic model of diffraction based on the uniform theory of diffraction has been used in the developed code. For the sake of simplicity, the method is presented in 2-D.