Circuit Design for Highly Sensitive RF-Powered Wireless Sensor Nodes

Abstract

Emerging applications such as Internet of Things (IoT), smart buildings and warehouse inventory management are important driving forces behind the development of Wireless Sensor Nodes (WSNs). With future advancements made in the semiconductor industry, these WSNs are expected to become smaller, cheaper, more reliable and with improved functionality. The prospect of energy scavenged WSNs is to eliminate the burden of battery replacement, thereby significantly saving on maintenance costs in large WSN networks. This dissertation focuses on the research, design and implementation of various circuit blocks and the system integration of energy scavenged WSNs used in the aforementioned applications. To select a suitable energy harvester, four different energy harvesting approaches are discussed: vibrational, thermal, photovoltaic and RF. Of these harvesters, it shows that RF-powered WSNs have the distinct advantage over WSNs using other forms of energy harvesting that they are low cost and can operate wirelessly in a large variety of applications, even in cold, dark and static environments. Moreover, additional advantages such as utilizing a dedicated RF source for both energy harvesting as well as the generation of a reference frequency greatly reduces the complexity and power consumption of the WSN.