Space mapping design method for an antenna transducer of a bend sensor RFID tag

This work presents a fast design method for an RFID antenna, used as a transducer, to realize an RFID bent sensor tag. The method exploits a space mapping technique, using a coarse circuit model (CM) and a fine electromagnetic model (EM). The CM represents, in a time efficient way, the antenna transducer states to fast evaluate the sensor tag efficiency. The EM model is then used to verify the sensing states and to rapidly prototype the antenna. To demonstrate the procedure, the corresponding EM-based and CM input impedances of a T-matched dipole are compared for several sensing states; the maximum relative error between the CM model and the EM simulation is lower than 15% and 1%, for the antenna impedance real and imaginary parts, respectively. This is observed over a frequency band of 840 − 890 MHz. Finally the bending sensor tag efficiency is computed and design rules for its optimization using the CM model are discussed