Multi-band simultaneous inductive wireless power and data transmission

In the FP7 European project SmartFiber, a structural health monitoring system that can be fully embedded in composite materials is being developed. In order to provide the embedded system with enough power and to extract the sensor data, inductive coupling technology at 125 kHz and 13.56 MHz is used, respectively. In this paper, it will be demonstrated how both wireless links can coexist together, using the same physical space in form of concentric planar coils and achieving high amounts of power (3.3 W) and high data rates (424 Kbps) at relatively long distances (5 cm). The main challenge is to achieve a reliable communication that deals with the strong self-interference due to the power link. The transmission system also has to deal with the fiber material itself, which can detune antennas and damp signal strength. This paper will show the system architecture, the details from the circuit design with respect to the coexistence as well as measurements of the system performance.