Ricerc@Sapienza

In this paper, preliminary results of variations as a function of applied pressure in the reflection coefficient of a planar patch resonator, placed in contact with cultural heritage stone materials, will be presented. The general aim of the experimental project is to correlate the resonant frequency of the planar sensor, for the different pressures applied to the resonator, with the different levels of water content θv of the tested stone material.

In this work, a noninvasive microwave-based system for monitoring water content of Cultural Heritage stone
materials is presented. In particular, by placing a planar resonator in contact with the stone sample, an experimental
relationship between resonant frequency and water content is obtained.
To verify the suitability of the system, experimental tests are carried out on several types of stones: gentile;
leccese; carparo; red brick; and red brick fabricated at high temperatures. The first three types of stones are

In this work, the dielectric permittivity of pietra gentile and pietra leccese (two kinds of stone typically
found in Cultural Heritage structures of Southern Italy), for different levels of moisture content, was characterized.

Monitoring water content in cultural heritage materials through non-invasive and easy-to-use TDR/TDT (time-domain reflectometry / time-domain transmission) measurement systems has the potential to enhance conservation/restoration activities. In this study, two different probes for TDR/TDT technology, Square Patch Resonator (SPR) and Split Ring Resonator (SRR), were compared. The two probes were tested on two different materials (leccese and gentile stone), each one of them at three different levels of water content.