The goal of our work is to optimise the supply chain management of industrial assets with UHF RFID system. This allows simple identification. In this work, we try to go further and enrich the identification information with information about the conditions of the connected assets. To avoid any maintenance operation, we realise an energy harvesting circuit to provide the needed energy to the connected sensor. In this paper, we present the conception of an autonomous connected sensor, which works in UHF RFID band. We set up the global architecture of the measurement system and we focus mainly on the energy supplier circuit and its improvement.