Wearable devices are ideal for personalized electronic applications in several domains such as healthcare, entertainment, sports and military. Although wearable technology is a growing market, current wearable devices are predominantly battery powered accessory devices, whose form factors also preclude them from utilizing the large area of the human body for spatiotemporal sensing or energy harvesting from body movements. E-textiles provide an opportunity to expand on current wearables to enable such applications via the larger surface area offered by garments, but consumer devices have been few and far between because of the inherent challenges in replicating traditional manufacturing technologies (that have enabled these wearable accessories) on textiles. Also, the powering of e-textile devices with battery energy like in wearable accessories, has proven incompatible with textile requirements for flexibility and washing. Although current e-textile research has shown advances in materials, new processing techniques, and one-off e-textile prototype devices, the pathway to industry scale commercialization is still uncertain. This paper reports the progress on the current technologies enabling the fabrication of e-textile devices and their power supplies including textile-based energy harvesters, energy storage mechanisms, and wireless power transfer solutions. It identifies factors that limit the adoption of current reported fabrication processes and devices in the industry for mass-market commercialization. INDEX TERMSWearables, e-textile devices, e-textile power sources, e-textile manufacturing and scalability.

The design of dynamic wearable wireless power transfer systems (WPT) possesses multiple challenges that affect the WPT efficiency. The varying operation conditions, such as the coils' coupling, and operation in proximity or through the human body, can affect the impedance matching at the resonant frequency. This paper presents a high-efficiency wearable 6.78 MHz WPT system for smart cycling applications. Resonant inductive coupling using dual-receiver textile coils is proposed for separation-independent WPT, demonstrated in a smart cycling glove, for transferring energy from an on-bicycle generator to smart-textile sensors. The effects of over-coupling in a dynamic WPT system have been investigated analytically and experimentally. The embroidered coils efficiency is studied in space, on-and through-body.The measured results, in space, show around 90% agreement between the analytical and experimental results. To overcome frequency-splitting in the over-coupling region, an asymmetric dual-receiver architecture is proposed. Empirical tuning of the lumped capacitors is utilized to achieve resonance at 6.78 MHz between the fundamental frequency and the even mode split frequency. Two different coil sizes are utilized to achieve separation-independent efficiency in the tight coupling region on-and off-body, while maintaining a Specific Absorption Rate (SAR) under 0.103 W/kg. The presented system achieves a peak efficiency of 90% and 82% in free space and on-hand respectively, with a minimum efficiency of 50% under loose and tight coupling, demonstrating more than 40% efficiency improvement over a 1:1 symmetric transmit and receive coil at the same separation.INDEX TERMS Coil, electronic textiles, impedance matching, resonant coupling, wireless power transfer.

In Radio Frequency (RF)-powered networks, peak antenna gains and path-loss models are often used to predict the power that can be received by a rectenna. However, this leads to significant over-estimation of the harvested power when using rectennas in a dynamic setting. This work proposes more realistic parameters for evaluating RF-powered Body Area Networks (BANs), and utilizes them to analyze and compare the performance of an RF-powered BAN based on 915 MHz and 2.4 GHz rectennas. Two fully-textile antennas: a 915 MHz monopole and a 2.4 GHz patch, are designed and fabricated for numerical radiation pattern analysis and practical forward transmission measurements. The antennas' radiation properties are used to calculate the power delivered to a wireless-powered BAN formed of four antennas at different body positions. The mean angular gain is proposed as a more insightful metric for evaluating RFEH networks with unknown transmitter-receiver alignment. It is concluded that, when considering the mean gain, an RF-powered BAN using an omnidirectional 915 MHz antenna outperforms a 2.4 GHz BAN with higher-gain antenna, despite lack of shielding, by 15.4× higher DC power. Furthermore, a transmitter located above the user can result in 1× and 9× higher DC power at 915 MHz and 2.4 GHz, respectively, compared to a horizontal transmitter. Finally, it is suggested that the mean and angular gain should be considered instead of the peak gain. This accounts for the antennas' angular misalignment resulting from the receiver's mobility, which can vary the received power by an order of magnitude.INDEX TERMS Antennas, Body Area Networks (BAN), electronic textiles, energy harvesting, Internet of Things, ISM bands, RF energy harvesting, wearable antenna, wireless power transfer.

Integrated health monitoring is beneficial but due to reliability, weight, size, wiring and other constraints, the incorporation of instrumentation onto aircraft propulsion systems is limited. Conventional wired sensing systems are not always feasible due to size, weight constraints, and issues associated with cable routing. This paper presents an integrated and selfpowered wireless system for high temperature (above 125 • C) environments powered by a thermoelectric generator for bearing condition monitoring. Thermoelectric generator with internal oil cooling chamber is proposed to achieve higher energy output for small temperature gradient recorded in the jet engine in comparison with other thermoelectric generators with heat sinks. The experimental results demonstrate that, under a simulated engine environment, the thermoelectric generator can provide sufficient energy for a wireless sensing system to collect environmental data every 46 s, and transmit every 260 s, during the critical takeoff phase of flight and part of cruise.

Abstract-The promise of smart cities offers the potential to change the way we live, and refers to the integration of IoT systems for people-centred applications, together with the collection and processing of data, and associated decision making. Central to the realization of this are wearable and autonomous computing systems. There are considerable challenges that exist in this space that require research across different areas of electronics and computer science; it is this multidisciplinary consideration that is novel to this paper. We consider these challenges from different perspectives, involving research in devices, infrastructure and software. Specifically, the challenges considered are related to IoT systems and networking, autonomous computing, wearable sensors and electronics, and the coordination of collectives comprising human and software agents.