This work presents millimetre wave measurements of the reflection coefficient for different dielectric materials widely used in our daily life. The measurements (i.e., monostatic measurements) are done by using a frequency modulated continouos wave radar with a dielectric lens antenna. The main results are done for the following materials: Polytetrafluorethylen, Polyvinylchloride, gypsum plasterboard, and autoclaved aerated concrete. The measurements are done in the frequency range from 68 GHz to 92 GHz.