All mechanical structures are subject to deformation and cracks, due to fatigue, stress and/or environmental factors. It is therefore of uttermost importance to monitor the mechanical condition of critical structures, in order to prevent catastrophic failures, but also to minimize maintenance costs, i.e. avoid unnecessary inspections. A number of technologies and systems can be used for this purpose: among them, the ones proposing the use of wireless passive crackmeters have a strong impact potential, in terms of simplicity of installation and measurement and low cost.
The present work hence shows a crack width wireless radio frequency identification (RFID) sensor, developed for applications on various materials (such as concrete and metal) and able to detect sub-millimeter deformations occurring on the object on which it is placed. A design method based on high sensitivity phase detection is shown.