Permittivity-Based Water Content Calibration Measurement in Wood-Based Cultural Heritage: A Preliminary Study

Sensors

Andrea Cataldo¹  Emanuele Piuzzi²  Livio D’Alvia³  Zaccaria Del Prete³ 

[1] Department of Engineering for Innovation, University of Salento, 73100 Lecce, Italy;Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, 00184 Rome, Italy;Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, 00184 Rome, Italy;

关键词: calibration procedure;    water content measurement;    dielectric permittivity measurement;    cultural heritage;   

DOI  :  10.3390/s22062148

来源: DOAJ

【 摘 要 】

In this work, the dielectric permittivity of four kinds of wood (Fir, Poplar, Oak, and Beech Tree), used in Italian Artworks and structures, was characterized at different humidity levels. Measurements were carried out using three different probes connected to a bench vector network analyzer: a standard WR90 X-band waveguide, a WR430 waveguide, and an open-ended coaxial probe. In particular, we investigated the dispersion model for the four wood species, showing how a log-fit model of the open-ended data presents a determination coefficient R² > 0.990 in the 1–12 GHz frequency range. This result has proven helpful to fill the frequency gap between the measurements obtained at different water contents with the two waveguide probes showing an R² > 0.93. Furthermore, correlating the log-fit vertical shift with the water content, it was possible to find a calibration curve with a linear characteristic. These experimental results will be helpful for on-site non-invasive water monitoring of wooden artworks or structures. Moreover, the final results show how the open-ended coaxial probe, with a measurement deviation lower than 7% from the waveguide measurements, may be used directly as a non-invasive sensor for on-site measurements.

【 授权许可】

Unknown