Monitoring Health Status and Quality Assessment of Leaves Using Terahertz Frequency

This paper presents a new and non-invasive electromagnetic technique that utilizes the terahertz frequency waves to monitor the plant health. To do so, the water content of a plant leaf is obtained using the measured scattering response in the frequency range of 0.75 to 1.1 THz. Leaves of three commonly used herbs were observed for four consecutive days and the electromagnetic material parameters such as the permittivity were extracted using a material characterization algorithm. The decreasing moisture level and in turn the plant health can therefore be directly inferred from the leaf permittivity which approaches to that of free space with the passage of days.