In Vivo Dielectric Characterization and Equivalent Circuit Modeling of Mangifera indica L. Stem Tissue for PBC Applications

The rapid global population growth is driving increased food demand, requiring innovative agricultural solutions amid limited resources. A key advancement in smart agriculture is directly monitoring plants and crops instead of their environment. Plant Body Communication (PBC) is a novel and innovative technique that uses a plant's biological tissue to transmit signals, enabling seamless integration of sensors on, in, and/or near the plant with a single gateway. This gateway supports real-time plant monitoring and delivers essential electric and/or magnetic signals at any growth stage. This comprehensive process is grounded in the accurate measurement of dielectric properties, their characterization, and the equivalent electrical circuit modeling of plant tissues- a crucial aspect of this research that is instrumental in implementing the PBC technique. This paper reports the measurement of the dielectric properties of Mangifera indica L. stem tissue using a Physical Property Measurement System instrument incorporated with an LCR meter from 4 Hz to 4 MHz. Furthermore, the parametric modeling of the dielectric spectrum, based on a multiple Cole-Cole model with up to two poles, is derived using the non-linear least squares method to represent the frequency-dependent variations of permittivity up to two relaxation processes. Additionally, complex impedance spectroscopy is presented and analyzed with the plant tissue's biological analogy to develop an electrical circuit model (ECM) with parameter values fitted to the measured data. PBC shows promise as a future agricultural method in precision agriculture for year-round plant growth monitoring and nutrient deficiency diagnosis, paving the way for efficient and sustainable farming.