X-Band RFID System Exploiting Doppler-Based Microwave Motion Sensors

In the future, the need to identify and sense objects through ultra-low-power or zero-power communication mechanisms will be more crucial than now. Backscattering-based radiofrequency identification (RFID) technology could still play a major role through the possible implementation of low-power identification (ID) and communication directly over other technologies. In this work, RFID capabilities are introduced over the X-band microwave motion sensor (MMS), typically used to detect and locate objects. Specifically, the concept of offset-carrier backscattering modulation is exploited to design a 10.525 GHz RFID system where the reader is purposely and slightly modified commercial and low-cost MMS (a few euros) to make the technology actually reliable. The transponder is instead a new microwave device capable of backscattering an MMS compatible wave modulating ID code and sensor data. The proposed RFID-over-MMS system has been designed, prototyped, and tested to verify the appropriateness of the proposed approach.