Effects of inaccuracy of material permittivities on ray tracing results for site- specific indoor propagation modeling

The complex dielectric constants of building materials are present in the reflection, transmission and diffraction coefficients of the ray tracing formulation. Any deviation of the dielectric constants included in ray tracing simulation from the actual material properties may be a source of inaccuracy of the simulation results. This paper explores the sensitivity of ray tracing results to the inaccuracy of the dielectric constants of building materials. To do this, the real and imaginary parts of the dielectric constants are considered as random variables to account for the present uncertainty. The propagation of uncertainty in the ray tracing simulation is then obtained by means of the Monte Carlo analysis. Simulation of a typical office environment at 2.44 GHz shows that the path gain is almost insensitive of the inaccuracy of the dielectric constants whereas rms delay spread exhibit much more sensitivity.