Technical challenges for the integration of passive HF RFID technology in FRP composite materials

In this paper the influence of fibre-reinforced plastic (FRP) composite materials on passive high frequency (HF) radio frequency identification (RFID) systems is evaluated. Firstly, a simulation model of a fabricated antenna coil has been developed. Furthermore, a carbon-FRP (CFRP) composite material sample has been characterized by measurements and the obtained parameters have been also included in the model. Measurements with the fabricated antenna have been conducted and results show that the shorter the distance between the antenna and the CFRP material, the bigger is the performance degradation. For example, at a distance of 5 mm the resonance frequency increases from 13.56 MHz to almost 16 MHz. The measurements have also been used to validate the developed simulation model, which can help to predict the effect of the CFRP material on the antenna performance and thus design a proper matching network that compensates this effect. This was also demonstrated by re-tuning the previous antenna coil and getting the resonance frequency back from 16 MHz to 13.56 MHz, both in simulation and measurement.