Optimization the effects of Asphalt and Soil on Underground Magneto-Inductive Communication and Localization

In this paper, an electrical model of RFID system for optimization of the effects of asphalt and soil on subsurface magnetic induction communication and location is performed. On the analysis of the model, it is found that the reader coil antenna is not in resonant state when it is near the asphalt or concrete or soil. Therefore, it needs isolation from the asphalt or concrete or soil and redesign. Furthermore, by comparing the electrical parameters of RX loop in the air and in the soil, it is shown that the RX coil is embedded in soil or other material without any change, will exhibit a Q-factor that is not maximum at resonant with the same frequency in air which in turn significantly reduces the RFID system’s wireless efficiency. Thus, a redesign of RX coils embedded in soil is presented. Experimental results show that the best material to enclose the antenna of RX coil is the plastic board box, the electrical parameters are close to those in air. Moreover, the method of reducing the mutual inductance and compensating inductance for slowing down the change of Q-factor is determined by the investigation of the complex resistance, inductance and Q-factor of the reader antenna. Therefore, the theoretical model, experimental conclusion and optimization method proposed in this paper are of great benefit to the development of asphalt and soil on subsurface magnetic induction communication and location.