Battery-free Bluetooth Low Energy Wireless Sensor Powered by Radiative Wireless Power Transfer

This paper addresses the design and the characterization of a battery-free Bluetooth Low Energy (BLE) wireless sensor node powered by radiative wireless power transfer. The battery-free sensors node, as part of a wireless meshed network, is optimized and is able to perform physical measurements (temperature and humidity) and share these measured data over the Internet through the wireless network. It operates by using a standard capacitor of 220 μF as a storage element and is remotely powered by a dedicated RF source using a radiative wireless power transfer. The main task initialization, sensing and broadcasting the measured data by using a BLE protocol requires only 1.2 mJ of energy per task. More the periodicity of physical measurements can be roughly controlled by controlling the radiated power of the RF source.