Energy Autonomous UWB Localization

In the new scenarios foreseen by the Internet of Things (IoT), industrial and consumer systems will be required to detect and localize tagged items with high accuracy using cheap, energy autonomous, and disposable tags. This paper discusses system-level and circuit-level aspects to be adopted for future generation passive radio-frequency identification (RFID) tags with localization capabilities. It is argued that RFID-enabled localization strategies, combining ultra-wideband (UWB) backscattering for communication/localization purposes and UHF for “on demand” powering of battery-less tags can be successfully exploited to this purpose. The proposed architecture adopts a small number of reference nodes, acting both as UWB readers and as UHF power sources. Architectural and circuital considerations on different design choices for the UWB-RFID tag are discussed, focusing on available off-the-shelf components. Power budget constraints for UWB backscattering operation and UHF wireless powering are derived in worst-case conditions. Furthermore, the simulation results, verified with experiments, prove the feasibility of cm-level localization accuracy at distances of several meters even in indoor scenarios where multi-path fading might be present.