Patent ID: 7551058

Claim:
A sensor for monitoring an environmental parameter in concrete comprising: (a) an enclosure for embedding in concrete; (b) a detecting means connected to the enclosure for detecting at least one environmental parameter in concrete, the detecting means comprising at least one capacitive element for measuring capacitive change; (c) an active material connected to the enclosure, (i) the active material being liable to respond to the environmental parameter, and (ii) the active material being operably connected to the capacitive element; (d) a RFID chip mounted within the enclosure, the RFID chip being operably connected to the detecting means; (e) an antenna operably connected to the RFID chip, (i) the antenna being operably connected to the detecting means, and (ii) the antenna being part of an L-C circuit whose resonance frequency shifts within an assigned frequency band, and (f) a transceiver electromagnetically coupled with the antenna, wherein the transceiver is operably connected to a means for measuring the change in resonance frequency of the sensor's L-C circuit.