Moisture-Dependent Dielectric and Microwave Scattering Properties of Tectona grandis Leaves at X-Band Frequencies

The present study investigates the effect of moisture content on the dielectric and microwave scattering properties of Tectona grandis tree leaves at X-band frequencies. The dielectric behaviour of vegetation is strongly influenced by its moisture content because water has a relatively high dielectric constant compared with the dry constituents of leaves. In this work, Tectona grandis leaves with different moisture levels are characterized over the X-band frequency range using a microwave measurement technique. The dielectric constant and associated loss were measured using the waveguide cell method. Scattering coefficients were then calculated from these dielectric values employing a perturbation model suitable for slightly rough surfaces. Results show that the scattering coefficient increases substantially with higher leaf moisture content (MC %). At the same incidence angle, scattering coefficients are consistently higher for vertical polarization than for horizontal polarization. The results are expected to demonstrate a significant relationship between leaf moisture and microwave interaction, which can be useful for vegetation monitoring, moisture estimation, microwave remote sensing, and agricultural applications.