Metamaterial transmission line resonators for structural moisture sensing in buildings

This paper presents novel metamaterial moisture sensors based on composite right/left-handed (CRLH) transmission line resonators, applicable for moisture measurements in brick and stone walls. Metamaterials are periodic structures consisting of series capacitors and shunt inductors with a periodicity well below the wavelength that can have properties similar to homogeneous materials. For sensing applications, metamaterial structures exhibit high sensitivity and the advantage of scalability in frequency and size as well as the ability of conformal implementation to the sensing task [1-2]. For proof of concept, a reflection type and a transmittance type sensor for implementation in small boreholes are realized and tested in a dedicated measurement setup.