Metamaterials based passive wireless sensor for concrete structures

—Increasing attention has been payed to wireless passive sensors because of the ever-increasing demand for long-term and accurate monitoring of chloride ion penetration and structure of concrete infrastructures. Extraordinary properties of metamaterials results in applications in sensors. In this study, a wireless passive SRR metamaterials based sensor system was designed and manufactured which was used to detect Cl− concentration and thickness of concrete. CST was used for simulation and observation of the performance of metamaterials sensors in X-band (8–12 GHz). High Q and sensitivity sensors were designed by continuously adjusting the dimensions of the SRRs. X-band microstrip antenna was designed by HFSS and the sensing performance of the proposed sensor system is simulated and experimental measured. The results demonstrate the feasibility of the wireless passive sensor system. The system was used to test Cl− and thickness of concrete structure and the experimental results indicate the theoretical significance and practicality.