Space-Filling Electromagnetic Skins for the Wireless Monitoring of Surface Defects

Polymer-based objects (cable harness, gaskets, tires) are exposed, during their lifetime, to mechanical and chemical stress that often generates surface defects like crack and scratches. Early detection of signs of aging may enable a Predictive Maintenance to extend the life of the object and avoid severe failures. For this purpose, Space Filling Curves (SFC) are here proposed as an artificial electric skin, suitable to envelope a surface to wireless detect the presence of small aging signs by resorting to an electromagnetic backscattering platform. Size and resolution of the skin can be controlled by just two parameters and multiple skin cells can be arranged together to tessellate a large surface in order to even identify the position of the defect. By following a theoretical analysis of the sensor-oriented properties of SFCs, and in particular of the Gosper-Fukuda family, the feasibility of the idea is demonstrated by the way of preliminary experiments with a Radio Frequency Identification (RFID) IC, providing a 1-bit anti-tamper port.