Akademik Veri Yönetim Sistemi
IEEE Sensors Journal, 2026 (SCI-Expanded, Scopus)
A wireless and passive sensing system is demonstrated for measurement of moisture content (MC) of trees. The system is based on a nested split-ring resonator (NSRR) sensor coupled with an antenna. Complex permittivity changes due to MC variation in a tree branch shifts the resonance frequency of the sensor which can be monitored through the antenna in near field. Transformation of frequency shift to MC is achieved by first performing a dielectric characterization of a drying tree branch through a perturbed cylindrical cavity resonator, in which complex permittivity of the tree species is obtained as a function of MC through perturbation theory. This data is then utilized in full-wave electromagnetic simulations of the wireless sensing system in which the dependence of NSRR frequency on MC and sample radius is characterized. Finally, calibration lines obtained via the simulations are used as a reference for converting the measured frequency shift into MC dynamically. For proof of concept, cavity characterization for 14 different tree species are presented, and results of in vitro measurements by the wireless system performed on 4 different tree species are shown. It is demonstrated the the system can accurately capture and convert frequency shift into dynamic MC, which can be utilized for early detection and/or prevention of wildfires.