Development and characterization of an RFID tag for soil moisture sensing.
Radio Frequency Identification, tag sensor, precision agriculture, soil moisture.
Radio Frequency Identification (RFID) technology is one of the fastest growing wireless communication services in recent years, from a simple identification service to has become a ubiquious sensing technology. The two main components of an RFID system are the tags and the reader that allows the identification of the tags. Some studies show that the tag itself can act as a sensor, associating changes in the electromagnetic parameters of the tag with the environment variables to be monitored. In the precision agriculture sector, the use of RFID technology with sensors has been gaining prominence as an opportunity for research, development and innovation. Current works show the possibility of measuring soil moisture using RFID tags in the Ultra High Frequency (UHF) range. For this measurement, changes in the dielectric properties of the soil caused by the humidity level may be related to changes in the electromagnetic parameters of the tag. Therefore, this work has the objective of analyzing the electromagnetic effects caused on RFID tag immersed in typical soil of the brazilian northeast, considering also the variation in the moisture level of this soil. The proposed tag will be based on a microstrip antenna with multilayer formed by periodic Fibonacci structures printed on the substrate. Then, the analysis of the effects caused by soil moisture will determine a tag model that is able to relate the soil moisture variation typical of the northeast to the return loss within the frequency range regulated by (ANATEL, of portuguese Agência Nacional de Telecomunicações) for UHF RFID systems in Brazil.