On the Use of a Lower Frequency in Finite-Difference Simulations for Urban Radio Coverage

The Finite-Difference Time-Domain (FDTD) is not just one of the most accurate propagation prediction methods but also one of the most computationally intensive models, especially when simulating big areas such as urban environments. To overcome this problem, one common approach is to perform simulations at a much lower frequency than that of the real system, and to calibrate the simulation parameters to adjust the frequency response of the materials. In this study a theoretical analysis of the consequences of applying such frequency reduction is performed. To compare the theoretical study some numerical experiments are conducted and matched to the analytical results. Finally, the error of the simulations at lower frequencies is evaluated, allowing us to obtain an explanation for the observed behavior.