A Three-Port Zero-Power RFID Wireless Sensor for IoT Applications

This paper proposes a novel battery-less wireless sensor architecture. The sensor architecture is fully passive which integrates a UHF RFID with a capacitance-based sensor. The sensor passively varies the phase of the backscattered RFID signal based on the sensed value. The phase alteration is easily determined at the receiver using a non-coherent IQ demodulation technique. The passive nature of this sensor keeps the read range of a regular UHF RFID tag unaffected, making it ideal for home and industrial applications.