Leaves Permittivity Estimation at 2.2 GHz for the Development of Propagation Models in Citrus Plantations

The massive use of sensors and actuators expected in Agriculture 4.0 will require a large deployment of wireless systems in agricultural environments. The planning of these radio communication systems is carried out using computer tools that incorporate propagation models. In this sense, it is necessary to propose propagation models for specific agricultural environments according to the type of plantation. In some of these models the trees are replaced by a layer medium, in which the electrical properties of leaves are specified in terms of their relative permittivity. This work presents permittivity measurements on citrus leaves, using a device based on a microwave cavity resonant method. Measurements were performed on shredded leaves inside a sealed Pyrex tube. At 2.2 GHz, the estimated values of the real and imaginary parts of the dielectric constant for lemon and oranges fresh leaves were 23.26 and 7.26, and 19.73 and 7.05, respectively.