The mechanism is described by which a passive UHF RFID tag coupled with a tuning circuit is integrated with a current transformer for sensing ac current in an electrical wire for smart power monitoring of individual appliances. A capacitance change in the tuning circuit results from a reverse bias voltage from the current transformer. The tuning circuit reactance is detected by a capacitance sensing RFID tag and the value is transmitted as a 5–bit sensor code which is directly related to the ac current drawn by an electrical load. The passive tag harvests energy and offers an innovative solution for energy management in future smart homes and for industry 4.0. As well as indicating current level, the technique can also be used to detect the ON and OFF state of an electrical device and is demonstrated to work for a rapidly switching load. The sensor is tuned for EPC Class 1 Generation 2 UHF RFID readers at 868 MHz.

This paper describes the development of a Direct Driven Resonant Radiator (DDRR) antenna for an ultra-low power UHF RFID tag system, integrating an accelerometer for movement tracking using a passive backscattering communications link. An outline of a system intended for healthcare applications involving wireless movement detection, such as therapeutic recovery exercises is described. The tag comprises of a UHF RFID transponder connected to a 4 cm (0.115λ) diameter, 1 mm thick (0.0028λ) skin-mounted antenna. Offbody read ranges of 3.6 m with 1 kB/s data communication are achieved. The DDRR radiation pattern is a limiting factor in movement tracking, offering only limited angles of detection, which could be improved with spatial diversity in the reader antennas.

This paper details the use of an acceleration measuring system which can transmit in real-time sensor data through UHF RFID to a computer. Existing methods of real-time transmission of sensor data rely on power-intensive Bluetooth or Wi-Fi technologies which result in devices that require large bulky batteries, this causes the overall device size to be high and thus can potentially cause issue during use. By harnessing status flags within a specific UHF RFID chip and custom reader software conforming to the EPC GEN2 standard, continuous streaming data rates of 5.2KBps were achievable. These enhanced data rates were shown to be reliable up to a range of 2.4M with above 99.99% data integrity. The power consumption of this methodology was found to be below 2mW during full power continuous transmission. In summary this paper outlines and lays the foundation for the use of UHF RFID to deliver sub-2mW low latency, high reliability streaming methods within the domain of on body transmission.

Spasticity is disabling feature of long-term neurological conditions that has substantial impact on people’ quality of life. Assessing spasticity and determining the efficacy of current treatments is limited by the measurement tools available in clinical practice. We convened an expert panel of clinicians and engineers to identify a solution to this urgent clinical need. We established that a reliable ambulatory spasticity monitoring system that collates clinically meaningful data remotely would be useful in the management of this complex condition. This paper provides an overview of current practices in managing and monitoring spasticity. Then, the paper describes how a remote monitoring system can help in managing spasticity and identifies challenges in development of such a system. Finally the paper proposes a monitoring system solution that exploits recent advancements in low-energy wearable systems comprising of printable electronics, a personal area network (PAN) to low power wide area networks (LPWAN) alongside back-end cloud infrastructure. The proposed technology will make an important contribution to patient care by allowing, for the first time, longitudinal monitoring of spasticity between clinical follow-up, and thus has life altering and cost-saving implications. This work in spasticity monitoring and management serves as an exemplar for other areas of rehabilitation.

Printed electronics using flexible substrates are an emerging area, allowing next-generation electronics to conform and flex with different surfaces, from human skin to clothing. In the hybrid integration, or sea-of-rigids, approach, conventional microchips are mounted onto (generally) plastic substrates such as polyethylene naphthalate (PEN), with (typically) printed silver tracks for interconnections between components. An ongoing research direction is to replace plastic substrates with biodegradable substrates and to replace silver tracks with non-heavy metal-based tracks. While the substrates and tracks form only part of an overall system, replacing them is a step towards increased sustainability and helps to meet net-zero goals for printed electronic systems. Previously, several papers have investigated printed carbon tracks for low-frequency analog sensing applications. This paper explores the feasibility of using printed carbon tracks on biodegradable substrates for high-frequency applications such as digital signaling over a Serial-Peripheral Interface (SPI). We investigate the printability, thermal stability, and electrical conductivity of carbon ink screen-printed onto six commercially available sustainable and flexible substrates. Our results demonstrate that multi-layer screen printing substantially reduced the electrical resistance of carbon tracks, enabling SPI communication at frequencies up to 16 MHz with three layers of carbon ink. A Natureflex™ substrate provided the best balance of printability, thermal stability, and electrical performance. Substrates such as greaseproof paper and ClearFilm PU showed potential for flexible electronics, but require further optimization. This study provides valuable insights into selecting and optimizing biodegradable substrates for high-frequency digital systems, supporting the move towards more sustainable printed electronics.