The experiment described in the following paper was performed to investigate RF propagation through different common building materials over a wide band of frequencies. The characterization is based on transmission power measurement. Results for the complex dielectric constant of each material over a frequency range of 2 to 16 GHz are presented. An internal multireflection model is used to compare experimental and theoretical transmission coefficients. A propagation loss model is developed using the attenuation induced by various walls. Finally, this path loss model is used to estimate coverage prediction of an indoor WLAN network at different frequencies.