Energy Autonomous RF Tags for Sensing and UWB Localization Applications

In the new scenarios foreseen by the Internet of Things (IoT), billions of smart devices are worldwide spread and connected to each other to provide sensing information or to detect and locate tagged items with high accuracy using cheap, energy autonomous, and disposable tags. In this context, the use of energy harvesting techniques to supply devices, nowadays, plays an important role in order to create energy autonomous systems able to reduce the use of batteries, by containing the infrastructure maintenance costs, for better environmental safeguard. Hence, by considering real scenarios in which tags can be placed, where only few µW are available as input source, low-power design aspects, strategies and policies have to be taken into account during the implementation approach. In order to cover all possible solutions, radio-frequency and light energy harvesting sources are considered to build battery-less nodes. Thus, PV passive tags for indoor and outdoor environments will be presented, which allows the creation of long range Wireless Sensor Networks (WSNs) used for environmental monitoring. In harsh scenarios where the presence of obstacles makes energy scavenging operations more critical, radio-frequency sources can be adopted to build battery-less, individually addressable, UHF tags, featuring high-directive behaviour with single-monopole structures or an orientation-independent usage through double-monopole architectures. UWB circuitry for localization purposes will be introduced in both configurations: transmitting and backscattering tag solutions adopting, in the first case, a customized protocol for the UHF link, while in the second one, a RFID integration compliant with European standard, by making this activity more attractive for the market.