Design of passive chipless wireless motion sensor using dual polarization effect

This paper presents a new principle of a passive chipless RFID wireless sensor for a rotational motion measurement and identification. The sensing and identification principles are based on a high quality factor substrate integrated cavity (SIW) resonator with dual antennas at two different angles. Depending on the angle difference between the dual antennas, the backscattered power generates a unique and identifiable pattern, which encodes in time domain both the rotational speed and the signature code of the rotating object. By the utilization of different dual polarizations, different sensor tags can be created with identification capabilities allow to distinguish between different sensors. The sensor operation principle has been investigated and analyzed experimentally for determining maximum number of possible codes using the response time of the reader. The choice of SIW for proposed sensor tag principle has the advantages of having high quality factor, low insertion loss, and high power capability as well as compatibility with planar microwave circuit technology.