RFID UHF protocol implementation in distributed sensor networks

In today's market significant segment is taken by the applications using sensors to track physical events in the surrounding environment. Market raise is particularly related to the distributed sensor networks based on the wireless communications (like Internet of Things IoT devices). One of the hardest challenges in this field is associated with the power supply requirements. Battery operated electronics is limited by the battery capacity and battery lifetime. This paper proposes solution based on the RFID EPC-Gen2-protocol-based readers supplying power to the sensor nodes, consisting of the microelectronic circuit and the associated sensor. Besides the power, RFID protocol provides means of wireless communication, without the need for the battery supply on the sensor node side. Analogue circuits for receiving and demodulating RF ASK modulated signal from the reader, and transmitting back the signal to the reader using backscattering technique, are presented. Subset of the command protocol is implemented to support data communication including sensor identification through the unique ID code and sensor reading in the form of the digital word provided by the on-chip ADC. RTL description for digital control is developed in VHDL and synthesized. The prototype is processed in UMC Mixed-Mode/RF 180 nm technology.