Coupling passive sensors to UHF RFID tags

Coupling passive sensor data to existing UHF RFID tags explores the possibility for low volume applications without designing a new tag ASIC. The existing UHF RFID system can be used to convey additional data by overlaying a coupling loop on the tag antenna and modulating vector backscatter. The design of the RFID passive sensor prototype is presented and the feasibility of this approach is demonstrated by the experimental results of the vector backscattered signals.