Magnetocaloric effect in M5XB2 family compounds

The purpose of work presented in this thesis is to investigate whether M5XB2 (M = Fe, Mn,V, Cr and X = Si, P) material system has potential as a room-temperature magnetocaloric application material by studying its crystal and magnetic structure, and magnetocaloric properties.

Accelerating Programmer-Friendly Intermittent Computing

The Internet of Things (IoT) is taking the world by storm, from smart lights to smart plant monitoring. This revolution is not only present in consumers’ homes, but companies are also looking for more and more ways to monitor every aspect of their production process. This transition to ubiquitous monitoring is made possible by extremely low...

Wide-Input-Range Power Conversion for RF Energy Harvesting and Wireless Power Transfer

This thesis presents the design and measurement of an RF energy harvesting and power management unit that operates across a wide range of available input power. The system comprises an adaptive impedance matching network, a single-stage cross-coupled differential-drive rectifier, a start-up charge pump, an adaptive buck-boost converter, a...

Micro Energy Harvesting from Low-Frequency Vibrations: Towards Powering Pacemakers with Heartbeats

Miniaturized vibration energy harvesters can provide an alternative to batteries in powering the billions of low power devices we use today by extracting power from ambient motion. Especially for implanted medical devices, these alternative power sources may be an attractive option to overcome the limitations on longevity and the replacement...

Continuous Sensing on Intermittent Power

Battery-free energy-harvesting devices have the potential to operate for decades, since they draw power fromvirtually unlimited energy sources, such as sunlight. However, ambient energy sources are volatile, and tiny harvesters can extract only weak power from them. Thus, small energy-harvesting devices operate intermittently: first, they charge...

Ambient-Energy Powered Multi-Hop Internet of Things

The Internet of Things (IoT) is one of the disruptive technologies in today’s connected world. The idea is to connect every thing to the Internet. IoT holds the key to many current and future technologies that will significantly influence the quality and sustainability of life. The vision of IoT is to enable large scalemonitoring and/or control...

Radio frequency energy harvesting and low power data transmission for autonomous wireless sensor nodes

Since the Internet of Things (IoT) is expected to be the new technology to drive the semiconductor industry, significant research efforts have been made to develop new circuit and system techniques for autonomous/very low-power operation of wireless sensor nodes. Very low-power consumption of sensors is key to increase battery lifetime or allow...

Circuit Design for Highly Sensitive RF-Powered Wireless Sensor Nodes

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...

An Empirical Approach Towards Zero Energy Networks (ZEN)

Information and Communication Technology (ICT) is changing the way we live and has become an essential part of our life. With the advent of Internet of Things (IoT), and Wireless Sensor Networks (WSN) in particular, the number of devices that are networked is increasing exponentially over the years. With the increase in number of ICT devices...

An FM-UWB Transceiver for Autonomous Wireless Systems

This thesis discusses the design and implementation of a transmitter and a receiver for an FM-UWB scheme in CMOS. The main challenge is to reach a power efficiency of better than 10 nJ/bit at a data rate of 100 kbit/s for both the transmitter and the receiver design. This thesis also discusses the design and implementation of a power management...

Structured Piezoelectric Composites: Materials and Applications

The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits their practical application to certain specific...

Smart Systems Integration for Autonomous Wireless Communications

Integration of sensors and wireless transceivers for system networking aims at emerging applications that are highly integrated, self-powered, and low cost, relying on efficient power management schemes to prolong lifetime, thus eliminating the need for batteries as a limited primary source of energy. These applications include: health...

Human Power Empirically Explored

Harvesting energy from the users’ muscular power to convert this into electricity is a relatively unknown way to power consumer products. It nevertheless offers surprising opportunities for product designers; human-powered products function independently from regular power infrastructure, are convenient and can be environmentally and...