Internet of Trees (IoTr) Implemented by Highly Dispersive Electromagnetic Sensors

The water intake is intimately related to the plantation growth and the resulting production quality. The monitoring and regulation of the water content allows the city governments and municipalities to optimally design the watering schemes leading to healthy plantations and saving of irrigation water in dramatic amounts. The proposed moisture assessment system is based upon a network of highly sensitive electromagnetic sensors that work on the concept of spectral dispersion. The high sensitivity of the dispersion-based sensors comes from its narrowband magnitude or phase spectral signature at resonance. The minimal change in the moisture content of a sample placed in the sensor's cavity is sensed by the resonance shift of this signature. When these sensors are connected in network configuration, the watering process of the whole plantation can be optimized cohesively. The concept of 'Internet of Trees (IoTr)' is particularly useful in the communities where water is found in scarcity such as the Gulf countries. In this article, we experimentally demonstrate the concept using a two-node passive prototype in the 4-6 GHz range by establishing relation between leaf moisture content and resonant frequency of the dispersive sensor. On the system level, we propose implementation of a representative network system based on LoRa protocol. The proposed sensor network is low-cost, self-calibrated and can derives its power from energy harvesting, through a solar.