Effective modeling of composite walls in hospitals for ray-optical wave propagation simulations

This paper deals with the simulation of wave propagation in hospitals in the frequency range from 600 MHz to 5.2 GHz. What makes wave propagation in hospitals different from that in other buildings is the special construction of the walls. Some of the walls contain metallic layers in their structure, e.g. operating rooms with CrNi-steel faced walls, X-ray rooms with lead shielding or MRT-rooms (magnetic resonance tomography) with an explicit EMC shielding often made of copper. Wave propagation in such rooms has not been simulated yet. This work uses a ray-optical simulation tool for this purpose. The walls are homogeneously modeled by multiple layers of different materials. The crucial point for an accurate modeling of the walls is the knowledge of the constitutive parameters for the different material layers. The results of extensive wave propagation measurements in four different hospitals are used for the determination of these parameters. The paper presents the determination of these parameters and their performance.