Influencing factors of moisture measurement when using microwave reflection method

Using microwave reflection for detecting moisture content in building materials is a known method. By combining sensor heads with different microwave penetration depths make it possible to generate 3D moisture content maps. This is a problematic and not easy task because several problems exist: interference between waves reflected from different layers, calibration accuracy, inhomogeneity of the material under the test etc. To interpret real measuring results several artificial moisture content distributions for measurements were built up. We describe rules to catch information about moisture distribution in depth of material from data measured with sensors with different sensing depths.