Millimeter-Wave (mmWave) communication enables high data rates but suffers from limited coverage and blockage. Network-Controlled Repeaters (NCRs), standardized in 3GPP Release 18, offer a cost-effective solution using analog beam-forming. This paper presents a software-controlled beamforming method for NCRs based on Taylor amplitude distribution to obtain extremely low sidelobe level. A 32-element phased array with phase-control ICs was implemented, and the radiation patterns were measured in an anechoic chamber at 28.0 GHz. The results confirm effective beam manipulation and sidelobe reduction, demonstrating the feasibility of software-defined NCR control.

Memristive associative learning has gained significant attention for its ability to mimic fundamental biological learning mechanisms while maintaining system simplicity. In this work, we introduce a high-order memristive associative learning framework with a biologically realistic structure. By utilizing memristors as synaptic modules and their state information to bridge different orders of associative learning, our design effectively establishes associations between multiple stimuli and replicates the transient nature of high-order associative learning. In Pavlov’s classical conditioning experiments, our design achieves a 230% improvement in learning efficiency compared to previous works, with memristor power consumption in the synaptic modules remaining below 11 μW. In large-scale image recognition tasks, we utilize a 20×20 memristor array to represent images, enabling the system to recognize and label test images with semantic information at 100% accuracy. This scalability across different tasks highlights the framework’s potential for a wide range of applications, offering enhanced learning efficiency for current memristor-based neuromorphic systems.

Fundus diseases are prevalent causes of visual impairment and blindness worldwide, particularly in regions with limited access to ophthalmologists for timely diagnosis. Current approaches to fundus disease diagnosis heavily rely on expert-annotated data and AI-assisted image analysis, offering advantages, such as improved accuracy and accessibility. However, the dependency on annotated data poses a significant challenge, especially in regions with limited resources. To address this challenge, we propose a label-free general framework based on self-supervised machine learning. We performed feature distillation on a large number of unlabeled fundus images and employed a linear classifier for the detection of different fundus diseases. In validation experiments on the public and external validation fundus data sets, our model surpassed existing supervised approaches, achieving a remarkable increase in the area under the curve (AUC) of 15.7%, and even outperformed individual human experts. Our approach offers a promising solution to the limitations of current diagnostic methods, enhancing the potential for early and accurate detection of fundus diseases in resource-constrained settings.

The combination of teleoperating robots and the Internet of Things (IoT) could be employed in many areas, including remote nursing and semi-mechanical control. However, it is known that subjects can quickly encounter physical and mental fatigue, which can potentially lower accuracy in teleoperation. To address this issue, this article presents a closed-loop teleoperation system based on multisensory fusion, visual, and haptic feedback within the IoT framework. Various sensors for electromyography, inertial measurement unit, and mechanical hand control system are deployed to obtain body signals from participants, subsequently processed by artificial intelligence methods. Resistive sensors are installed at the robotic hand side to learn the contact force between the robot hand and the grasped object. To allow the user to understand the contact force levels, a haptic interface is equipped to provide three-level mechanical vibrations. To help users identify and trace different objects, a region convolution neural network for detecting 100 different categories of things is constructed. In addition, the real-time control (delay$\mathbf {< } 110$ms) is offered by a tri-layered IoT architecture. The feasibility of the proposed technique is validated by a grasping task carried out by 20 volunteers. During experiments, it is observed that merely 10.8 s is averagely needed for participants in finishing the task, with a high average success rate of 97%. Besides, NASA-TLX questionnaire and maximum voluntary contraction test report that users suffer light mental and physical fatigue when the proposed technique is used.

Thin-film electronics has hugely benefitted from low-cost processes, large-area processability, and multifunctionality. This has not only stimulated innovation in display and sensor technology but has also demonstrated great potential for the integration of components for human-machine interfaces. For electronics to be deployed as sensor interfaces and signal processing, the quest for low power is compelling due to the inherently limited battery lifetime. This review will present the state of the art in thin-film electronics and demonstrate examples of low-cost printable transistors and biosensors that are flexible/stretchable for wearable and other applications. Ultralow-power design for thin-film transistors will be discussed from the standpoint of reducing both operating voltage and operating current, taking into account the challenges in meeting frequency requirements. Compact models for circuit design will be reviewed along with new insights into ultralow-power transistors and high-gain amplifier circuits. Finally, a concept for an integrated system comprising sensors and interfacing circuits will be demonstrated, which has the potential to enable batteryless operation.

Visual display of information is an obvious requirement in today,s highly digital world, and constitutes a powerful means of conveying complex information. This stems from the ability of the human eye and brain to perceive and process vast quantities of data in parallel. The history of visualizing information can be traced to the ancient era, when our ancestors carved images on cave walls and monuments. Mosaic art form emerged in the 3rd millennium BC, using small pieces of glass, stone, or other materials in combination to display information. These pieces are similar to pixels in the modern electronic display. The electronic display has become the primary human-machine interface in most applications, ranging from mobile phones, tablets, laptops, and desktops to TVs, signage, and domestic electrical appliances, not to mention industrial and analytical equipment. In the meantime, user interaction with the display has progressed significantly. Through sophisticated hand gestures, the display has evolved to become a highly efficient information exchange device. While interactive displays are currently very popular in mobile electronic devices such as smartphones and tablets, the development of large-area, flexible electronics, offers great opportunities for interactive technologies on an even larger scale. Indeed technologies that were once considered science fiction are now becoming a reality; the transparent display and associated smart surface being a case in point. Examines the market for interactive displays as the next omnipresent technology.

Amorphous oxide semiconductor thin film transistors and sensors constitute fundamental building blocks for a new generation of applications ranging from interactive displays and imaging to future electronic systems that are unconstrained by form factor. This makes the quest for high mobility materials processed at low temperatures even more compelling, to enable the layering of circuits and systems on plastic and possibly even paper substrates. Transparency is also an attractive feature that enables seamless embedding of electronics for the immersive ambient. This paper reviews the current status of the ubiquitous oxide semiconductor technology for flexible and transparent interactive displays, along with demonstrated examples of continuous thin film and nanowire systems for the transistor and sensor. Issues related to photo-sensing and active matrix operation are discussed along with solutions addressing the problem of threshold voltage instability and its compensation for fast recovery, particularly after light stress. Physics-based compact models for expedient design and simulation of analog and digital circuits are reviewed along with examples of key system building blocks. Finally we attempt to conceptualize a thin film transistor (TFT)-based fully heterogeneously integrated and autonomous system that can be realized using a combination of oxide and other technological routes.

Thin-film electronics in its myriad forms has underpinned much of the technological innovation in the fields of displays, sensors, and energy conversion over the past four decades. This technology also forms the basis of flexible electronics. Here we review the current status of flexible electronics and attempt to predict the future promise of these pervading technologies in healthcare, environmental monitoring, displays and human-machine interactivity, energy conversion, management and storage, and communication and wireless networks.

This paper presents a new current-programmed, current-output active pixel sensor (APS) based on a novel current scaling scheme and suitable for real time X-ray imaging (fluoroscopy) and a current mode CMOS readout circuit. The circuit is designed using hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) technology. The simulation results based on the measured characteristics of a-Si:H TFTs show that the proposed pixel circuit can successfully scale up the current data during readout and therefore provide higher gain compared with the conventional current mode APS circuits. The design can also compensate for characteristic variations (e.g. mobility and threshold voltage shift) in a-Si:H TFTs under prolonged gate voltage stress. The readout circuit exploits correlated double sampling (CDS) technique to reduce the offset current, low frequency noise and fixed-pattern noise (FPN) on the array operation.

Although current-programmed pixel circuits lead to a highly stable amorphous silicon (a-Si) active matrix backplane, they are prone to a long settling time due to the large parasitic capacitance coupled with the low mobility of a-Si thin film transistors (TFTs). This paper presents a fast-current source that can significantly improve the settling time of the a-Si active matrix. Also, to reduce the effect of mismatches a differential offset cancellation technique is introduced.

Presents an introduction to a special issue of Proceedings of the IEEE. Flexible electronics is entering an exciting phase in the technology development cycle. After a decade of fundamental materials and device research, we are now witnessing the first major push toward commercialization. Productization requires device architectures and materials processes that are reliable and suitably qualified for high volume manufacturing. While the focus of the July issue of the Proceedings of the IEEE was on electronic systems and applications, the theme of the current issue is on materials and device technology, process development, and manufacturing technology. The fifteen papers in this issue provide a good overview of the status of flexible electronic materials and manufacturing technology.

This paper addresses the low-temperature deposition processes and electronic properties of silicon based thin film semiconductors and dielectrics to enable the fabrication of mechanically flexible electronic devices on plastic substrates. Device quality amorphous hydrogenated silicon (a-Si:H), nanocrystalline silicon (nc-Si), and amorphous silicon nitride (a-SiN/sub x/) films and thin film transistors (TFTs) were made using existing industrial plasma deposition equipment at the process temperatures as low as 75/spl deg/C and 120/spl deg/C. The a-Si:H TFTs fabricated at 120/spl deg/C demonstrate performance similar to their high-temperature counterparts, including the field effect mobility (/spl mu//sub FE/) of 0.8 cm/sup 2/V/sup -1/s/sup -1/, the threshold voltage (V/sub T/) of 4.5 V, and the subthreshold slope of 0.5 V/dec, and can be used in active matrix (AM) displays including organic light emitting diode (OLED) displays. The a-Si:H TFTs fabricated at 75/spl deg/C exhibit /spl mu//sub FE/ of 0.6 cm/sup 2/V/sup -1/s/sup -1/, and V/sub T/ of 4 V. It is shown that further improvement in TFT performance can be achieved by using n/sup +/ nc-Si contact layers and plasma treatments of the interface between the gate dielectric and the channel layer. The results demonstrate that with appropriate process optimization, the large area thin film Si technology suits well the fabrication of electronic devices on low-cost plastic substrates.

While fabrication of active matrix organic LED (AMOLED) displays on plastic substrates continues to face technological challenges, stable electrical operation of thin-film transistor (TFT) pixel circuits under mechanical stress induced by substrate bending remains a critical issue. This paper investigates strain-induced shifts in hydrogenated amorphous silicon TFT characteristics and the compound impact on TFT circuit behavior. Measurements show that the magnitude of the shifts is determined by the direction of current flow in the TFT with respect to the bending stress orientation as well as bias conditions. Physically based compact models are developed that relate device characteristics to material behavior for design and optimization of AMOLED pixel circuits that can maintain immunity to bending stress. In particular, current mirror-based pixel circuits are presented that compensate for the long term threshold voltage shift and instantaneous strain-induced shifts in device characteristics.

We report a new formulation for computing the charge density of a multiconductor system in a homogeneous or multiple dielectric medium. The technique employs single-layer potential description to yield a Fredholm integral equation of the second kind, for which efficient numerical algorithms are available. Furthermore, the associated discretization matrix has improved conditioning. Here, we consider not only the potential but also the electric flux density, offering a direct means of controlling the overall computational accuracy and efficiency. The technique can be employed to extract parasitic coupling capacitance in VLSI interconnects and large-area imaging arrays, as well as electrostatic forces in microelectromechanical systems.

In this paper, we present simulation results of magnetic sensitivity for bipolar magnetotransistors using an equivalent circuit modeling approach. The magnetotransistors is suitably partitioned into inactive- and active-magnetic device regions where the latter is modeled using an appropriate circuit topology, based on magnetic field dependent resistors and voltage controlled current sources that account for the interaction of the magnetic field on the injected currents. The resulting equivalent circuit is generated and implemented into HSPICE and simulation results, and subsequent optimization, of magnetic sensitivity are obtained for various geometrical and technological parameters. The circuit approach presented here facilitates computer aided design (and optimization) of both sensor, the co-integrated circuitry, and their interactions, since it can all be done in the same environment.>

Two-dimensional numerical solutions to the system of partial differential equations governing galvanomagnetic carrier transport in magnetic-field-sensitive integrated bipolar transistors are presented. The equations are discretized using the finite box procedure with a variation in the standard Scharfetter-Gummel approach adopted for the current continuity equations. High-resolution computations of the potentials in the base region of realistic device structures and operating conditions show that the magnitude of the Hall voltage at the emitter-base junction is too small to cause any appreciable asymmetric minority carrier injection thus invalidating the widely invoked emitter injection modulation model. Measured data obtained using in situ Hall probes are in support of the conclusions derived from the numerical model.>

With the increasing need for microsensors, development of simulation tools (based on adequate physical models to facilitate microsensor analysis and design) is a crucial task. The authors review the variety of physical approximations, model equations, and boundary conditions along with an outline of pertinent numerical procedures used in the numerical simulation of semiconductor microsensors. In particular, physical microsensors for thermal, optical, magnetic, and mechanical measurands are considered and selected simulation results are presented.>