| This work considers the reception of radio frequency signals as a way to power wirelessly a passive strain sensor circuit, possibly on or embedded in the body of a concrete bridge. The received signal, sent by an interrogator device, generates a sinusoidal voltage in the terminals of the sensor circuit antenna. This voltage is then rectified, filtered and multiplied to generate a DC voltage that can be used to supply and activate the circuitry of the strain-sensor. Throughout, theoretical formulation and simulation are used as tools to prove the feasibility of different voltage multiplier circuits as charge pumps and transformers.; The design and fabrication theory of a novel threshold-voltage free RF- to DC-Voltage circuit is presented in chapter IV. The circuit is designed with MOSFET transistors. Chapter V reviews some of the potential open problems and opportunities in an interrogator-strain-sensor system based in totally different technologies. |
