Ultralow Power and Compact Backscatter Wireless Device and Its SDR-Based Reading System for Environment Monitoring in UHF Band

In this letter, we demonstrate the possibility to design a compact and ultralow power wireless node for environment sensing operating in the UHF band at 868 MHz. The wireless device is based on an ultralow power 8 b microcontroller associated with a digital temperature and relative humidity sensor. It communicates according to the backscattering principle to a software-defined radio (SDR) controlled by a graphical user interface developed in GNU Radio. The wireless node features a power consumption of 5 μA under 1.8 V, which is good enough for communicating data with a packet error rate of 10% at 110 b/s over a range of 30 m in an indoor environment for a transmitting power of 20 dBm. The design of the wireless node and its SDR-based detection system is validated with wireless measurements both in an anechoic chamber and in the indoor environment.