# Introduction

When entering buildings in an urban database or building objects (walls) in an indoor database using the WallMan program from the WinProp software suite, material properties can be assigned to the buildings walls.

The empirical reflection model and diffraction model, that can be used in the ray-tracing propagation models within ProMan for the computation of the reflection and diffraction, uses empirical material parameters, the reflection loss (attenuation of the reflected wave in comparison to the incident wave) and the transmission loss (loss that an electromagnetic wave experiences when penetrating a wall).

Among the WinProp examples in the installation directory is a Microsoft Excel spreadsheet1 with material properties. This material table (the aforementioned Excel spreadsheet) contains a collection of physical material properties, ${\epsilon }_{r}{}^{\prime }$ and ${\epsilon }_{r}{}^{\prime \text{​}\prime }$ . It allows the computation of the mentioned empirical parameters from the physical values, depending on the frequency, the thickness and the roughness of the material.

The physical parameters were extracted from different sources. These sources are stated in the table.

1 Altair\2022.2\help\winprop\examples\ExampleGuide_models\Example-A03-Database_Materials.zip